Perfect Swiss Meringue Buttercream: Your Complete Guide
Swiss Meringue Buttercream (SMBC) is a fantastic frosting that looks great and tastes amazing. This silky, creamy frosting is made by heating egg whites and sugar before blending in butter. My updated recipe uses new techniques to reduce the buttery flavor and enhance the sweet vanilla taste, creating an ethereal, melt-in-your-mouth texture.
Welcome to my ultimate Swiss Meringue Buttercream guide!
We'll explore texture, aeration, and ingredient chemistry and learn how this frosting differs. Learn if it's suitable for your dessert and get the exact process to understand and customize your perfect Swiss Meringue Buttercream.
What is Swiss Meringue Buttercream?
My Swiss Meringue Buttercream is a type of True Buttercream, which is a large family of butter-based frostings made by creating stable emulsions.
Swiss Meringue Buttercreams are part of the True Buttercream Family and the larger Emulsions category. Frostings within the same group share similar characteristics, making it easy to navigate the world of frostings.
True Buttercreams are a family of stable emulsion frostings, where fat and water-based ingredients are mixed to create a thick, creamy texture. I often refer to these as “emulsion-based buttercreams.”
Generally, True Buttercreams are:
- moderately sweet,
- low in aeration,
- creamy and buttery in texture,
- able to create intricate piped designs and smooth cake sides,
- excellent in stability at room temperature and under pressure, and
- easily dyed and flavored.
So, what sets Swiss Meringue Buttercream apart from other Frostings?
Let’s get into the specifics of this buttercream:
What is the texture of Swiss Meringue Buttercream?
Swiss Meringue Buttercream is incredibly silky and smooth, with a melt-in-your-mouth texture. This is achieved through emulsification, which evenly distributes the meringue syrup throughout the butterfat, reducing the buttery flavor and texture. With a fat content of 30%, this buttercream has a moderate fat level.
I measure the aeration of my frostings, which is the percentage of volume occupied by air. Generally, my European buttercreams have low aeration, with Swiss Meringue Buttercream at around 12%. This means that for any given volume of frosting, 12% is air, while the rest comprises ingredients like butter, sugar, and water. For comparison, a highly aerated frosting like whipped cream can have up to 50% air.
Interestingly, the meringue itself offers very little in terms of aeration. Regarding contributing to texture, it seems as if the meringue plays a more significant role in the emulsion in breaking up the butterfat, which can feel heavy on the palate. If you’d like to learn more about this topic, read my Frosting Butter Guide.
Aeration is critical in understanding texture, affecting mouthfeel, greasiness, and spreadability. Although most of my emulsion-based frostings have low aeration, don’t let that deter you. Air isn’t the only factor influencing texture. In emulsion-based frostings, the high ratio of silky or creamy syrups interlaced with butterfat creates the luxurious, melt-in-your-mouth creaminess of the final buttercream.
What is the taste and flavor of Swiss Meringue Buttercream?
The overall flavor of this buttercream is sweetened vanilla butter. Swiss Meringue Buttercreams tend to be on the buttery side, but I’ve tempered this with my method, which creates a more balanced buttercream. Interestingly, the meringue doesn’t offer too much flavor. There is a hint of egginess, but for the most part, meringue offers a more overwhelming sweetness than anything else.
What ingredients do you need for Swiss Meringue Buttercream?
1 | EGG WHITES
Egg whites are the translucent, viscous fluid surrounding the egg yolk. In this frosting, they provide proteins and water. The proteins provide bulk and a bit of structure for the buttercream, whereas the water helps dissolve the sugar, yielding a creamier, smoother buttercream.
2,4 | POWDERED SUGAR
We use sugar two times in this recipe.
The first and larger amount is used to create the meringue syrup. For this, you can use either powdered or white granulated sugar. Although I have powdered sugar pictured here, I prefer to use granulated white sugar for the meringue step. American powdered sugars contain some starch (usually corn or tapioca), which can have a granular texture when used in large amounts. You’ll need to heat the syrup to a higher temperature to cook the starches, which I typically don’t do when using pasteurized or powdered egg whites. It’s just a pure sugary taste and smoother feel with white granulated sugar.
The second and smaller amount of sugar must be powdered, which sweetens and slightly aerates the butter.
3 | UNSALTED BUTTER
Butter provides fat, stability, flavor, and emulsifiers for this frosting. The unique combination of milkfats (around 80-84%) gives butter its wonderful creamy and spreadable texture. Butter is integral for True Buttercreams because it also contains various emulsifiers, which hold water-based and fat-based ingredients together. I always use unsalted butter in all my frostings and add salt based on taste.
5 | VANILLA EXTRACT
Vanilla extract is a general flavor enhancer for baked goods, and here, it is the primary flavoring element for this frosting. Extracts are generally interchangeable to make easy flavor modifications, but be sure to google it. (For instance, almond extract is potent, and you’d likely want to start with 25% of the amount of vanilla.) Also, vanilla bean paste is lovely here as it adds little vanilla bean specks throughout the frosting.
Natural vanilla extract tends to be dark brown, which can make the final frosting a bit cream-colored. If you’re trying to minimize this, consider a clear vanilla extract. These extracts are artificially flavored, but I like them in cakes and frostings.
6 | FINELY GRANULATED SALT
A pinch of salt enhances the flavor and balances the overall sweetness of this frosting. I typically use flaky kosher salt in my baking, but crispy salt bits are not appealing in frostings, so I exclusively use finely granulated salt. This allows the salt to dissolve more readily.
Do you need cream of tartar for Swiss Meringue Buttercream?
No, it’s not necessary. In previous versions of my Swiss Meringue Buttercream, you may have seen cream of tartar listed. This acidic ingredient helps unstick the egg proteins in the white from each other, yielding a fluffier meringue. Aeration of the meringue, however, is not as important as one might think for this buttercream. I go into more detail in the section below.
Step by step:
How to make my Swiss Meringue Buttercream Frosting
You can use raw or pasteurized (carton) egg whites for my recipe. The final buttercream will be nearly identical no matter which one you choose. In the tutorial below, I’m using raw egg whites, which require cooking to a specific temperature to kill food-borne illness-causing bacteria. Pasteurized egg whites do not need this, so I’ll note the changes in the protocol below.
STEP 1 | SET UP THE DOUBLE BOILER (BAIN-MARIE).
WHY:
Heating over a double boiler reduces the risk of overheating or heating a mixture too quickly. This method is commonly used in delicate preparations sensitive to extreme changes in temperatures and high heat, such as chocolate, custards, and meringues.
HOW:
Find a pot that allows a large bowl to sit on top. You don’t want to create a tight seal, as steam needs to escape. Here, I’m using a bit of foil, which allows for a slight gap for steam release (1a). Fill the pot with water so it’s within an inch of the bottom of your bowl, but don’t allow it to sit in the water (1b).
Some bakers told me it takes forever to heat the meringue syrup. This could be for a couple of reasons. The surface of the water is where the temperature of the fog is greatest, so you likely have too big of a gap between the bottom of the bowl and the surface of the water. Also, try to use a metal bowl, which conducts heat much more quickly and efficiently than glass. I’m using glass here because it’s easier for you to see what’s going on for demonstration purposes.
STEP 2 | HEAT THE MERINGUE SYRUP and WHIP THE MERINGUE (OPTIONAL).
WHY:
The meringue syrup is made of egg whites with sugar. You can use powdered or white granulated sugar here, as the meringue syrup will be heated high enough to dissolve any type.
You'll need a thermometer to heat this mixture to at least 160°F (71°C). This temperature is required to kill potentially pathogenic strains of Salmonella that may be present in raw eggs. After reaching this temperature, the mixture will be runny but safe to consume.
HOW:
Add sugar and egg whites to a large heat-proof mixing bowl (2a). (If you plan on whipping your meringue, use the bowl of your stand mixer.) Stir with a spatula until the sugar is evenly distributed (2b).
Once your double boiler is at a gentle simmer, use the foil to prop the bowl if necessary (2c), and place the bowl on top (2d).
Use a spatula to stir gently periodically and heat until the egg syrup reaches 160°F (71°C) (2e). Alternatively, pasteurized egg whites don’t need a thermometer. Use your fingers to gently (careful, it’s hot!) feel the meringue syrup and ensure no sugar granules (2f). Then, carefully remove the bowl and pour the hot syrup into a heat-proof bowl or measuring cup (2g).
Optionally, you can whip the meringue syrup to create a foam after it reaches the desired temperature. However, there is little difference in the final buttercream texture (see my Frosting Butter Guide). Note that if you use pasteurized egg whites, you'll get considerably less foaming than with fresh eggs. If you choose to do this, place the bowl in your stand mixer and use the whisk attachment to mix on high speed until stiff peaks form. Then, transfer the meringue to another bowl to prepare the frosting butter in the next step. There is no need to clean the bowl.
An important thing to note is that if you choose to whip the meringue syrup and it doesn’t whip up to your desired volume (or at all), it’s perfectly fine to proceed with the recipe.
Potential Pitfalls:
Some bakers told me it takes forever to heat the meringue syrup. This could be for a couple of reasons. The surface of the water is where the temperature of the fog is greatest, so you likely have too big of a gap between the bottom of the bowl and the surface of the water. Also, try to use a metal bowl, which conducts heat much more quickly and efficiently than glass. I’m using glass here because it’s easier for you to see what’s going on for demonstration purposes.
STEP 3 | PREPARE THE FROSTING BUTTER.
WHY:
A common complaint about True Buttercreams is their overly buttery taste and feel. To address this, I've developed a pre-conditioning method for the butter called "Frosting Butter." This technique aerates, pre-sweetens, and flavors the butterfat, ensuring an optimal creamy texture and temperature for emulsification, which is crucial for all True Buttercreams. The final buttercream is silky smooth and doesn't taste overly buttery. Additionally, frostings made with Frosting Butter are easier to re-whip without curdling after refrigeration or freezing. To learn more about the science of Frosting Butter, ready my guide here.
HOW:
For proper aeration, ensure the butter temperature is around 60-70 °F (15-21 °C) (3a). You don’t need a thermometer, but when the butter is at this temperature, you should be able to slide the whisk attachment into it with moderate pressure (3a, inset).
Add the butter to your mixing bowl and whisk on high speed for about 3-5 minutes, scraping down the sides at least once (3b). Aerated butter will still be paler, more voluminous, and ball up inside the whisk (3c).
Add the powdered sugar, vanilla extract, and a small pinch of salt (3d, e). Mix on high speed for another 2-3 minutes. You’ll notice that the butter is slightly glossier (that’s the sugar) but still has a good fluffy, voluminous texture that balls inside the whisk (3f).
STEP 4 | COMBINE THE COOLED MERINGUE SYRUP WITH BUTTER.
WHY:
Adding the meringue syrup in increments lets the butter emulsify gradually, producing a smooth and shiny buttercream.
HOW:
Ensure that your egg syrup (or foam) is at room temperature (4a) and add it to the Frosting Butter in 2 to 3 additions, whipping for about 1 minute after every addition (4b).
Once all the egg syrup has been added, mix for an additional minute on high speed (4c, d).
STEP 5 | SMOOTH AND ADJUST FOR FLAVORINGS.
WHY:
With all its wires, the whisk is much more efficient at emulsifying than a paddle with a thick singular wire. However, during the mixing process with a whisk attachment, we’ll inevitably mix in tons of air, which can further collect into larger air pockets. Switch the paddle attachment (one with a silicone edge, if you can), which smooths the frosting against the bowl and dramatically reduces the large air gaps in your final frosting.
HOW:
Switch over to the paddle attachment (5a) and smooth on the lowest speed for a few minutes (5b). Taste the buttercream and adjust for salt and vanilla. I have approval from my Mini Taste Tester (5c). The final buttercream will be silky smooth with a melt-in-your-mouth texture and ready to frost your cakes (5d).
Make Ahead and Storage Tips
Leftover Swiss Meringue Buttercream stores well in the fridge or freezer. It can also be made ahead of time for larger cake projects.
For a detailed tutorial, check out my How to Store Buttercream Guide.
Video
If you are a visual learner, check out this video below and I'll show you each and every step to make my buttercream. The protocol is a little different as I made this video a while ago but it still has some great visuals in it.
Read this before you begin
Measure by weight, if possible.
Measuring by weight is the best way for you to replicate my recipes. I develop recipes using ingredients (even liquids) measured in grams, which is why you see them listed first in the recipe cards. For measurements under 5 grams, I will typically only list the volumetric measurements (teaspoons, etc.), as most home scales are not precise for such small weights.
In most cases, I have converted grams to volumetric measurements (aka US customary units) for bakers who prefer this method. However, the measurements are not as precise and may have awkward proportions. The recipes should still work, but for the ultimate precision, try to use weight.
This is the OXO scale I use daily. I also purchased this budget version of a good scale, which I keep at my Mom’s house for baking. If you’re interested in other tools I use for my baking, I’ve compiled a list here.
Use room temperature ingredients.
All my ingredients should be used at room temperature, or 65-75 °F/18-24 °C. I will always indicate if you need something outside this range. If no details are given, room temperature is the default.
Pay attention to the ingredient descriptions.
I try not to be brand-specific, but I will always note an interesting result from a type of ingredient, be it negative or positive.
A specific note regarding salt: I use Diamond Crystal Kosher salt for everything on this site except for frostings. In frostings, you want the salt to dissolve more easily, and kosher salt tends to leave granules behind. If you substitute table salt (more finely granulated) for recipes that list kosher salt, you must use half the volume indicated in my recipes.
Substitutions are hard.
That’s not to say they’re impossible, though. For instance, in many cases, substituting reduced fat for whole milk (and thus reducing fat by less than 2%) will probably be fine. Using applesauce for oil or even Greek yogurt when sour cream is listed will definitely alter the fat content and adversely affect the crumb texture and density of the cake.
I experiment for hours to get these recipes to work for us. First, try to make them as written or use one of my tested substitutions, which I often dedicate a section to. Then, if necessary, you can make modifications afterward. Even then I would be pretty cautious, as substitutions are one of the hardest things to investigate in recipe development.
Read all the recipe instructions before beginning.
I’m in the “Pre-read the Chapter before Class Lecture” club... and I invite you to join! Baking new recipes can be intimidating, so let’s set you up for success. I want you to think about timeframes. Most fillings and frostings can be made ahead of time, and give you an extra day for mental space. Also, as you become a more proficient baker, you can anticipate and recognize steps. (“Oh, this has a meringue step, so I’ll need an extra clean bowl…” etc.) Ensure you go down the ingredient list and have everything at the right temperature.
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Vanilla Swiss Meringue Buttercream
40 g (2 tablespoons + 2 teaspoons) fresh or pasteurized (carton) egg whites*
75 g (5 tablespoons) sugar, granulated or powdered**
85 g (6 tablespoons) unsalted butter
20 g (2 tablespoons + 2 teaspoons) powdered sugar, unsifted
½ + ⅛ teaspoon vanilla extract***
small pinch of fine salt
For larger quantities or to pair with a cake recipe, go to my Cakeculator and choose “Vanilla Swiss Meringue Buttercream.
40 g (2 tablespoons + 2 teaspoons) fresh or pasteurized (carton) egg whites*
75 g (5 tablespoons) sugar, granulated or powdered**
85 g (6 tablespoons) unsalted butter
20 g (2 tablespoons + 2 teaspoons) powdered sugar, unsifted
½ + ⅛ teaspoon vanilla extract***
small pinch of fine salt
For larger quantities or to pair with a cake recipe, go to my Cakeculator and choose “Vanilla Swiss Meringue Buttercream.
- 121 g (½ cup) fresh or pasteurized (carton) egg whites*
- 225 g (1 ⅛ cup) sugar, granulated or powdered**
- 254 g (1 ⅛ cups) unsalted butter
- 60 g (8 tablespoons) powdered sugar, unsifted
- 2 teaspoons vanilla extract***
- ⅛ teaspoon fine salt
For larger quantities or to pair with a cake recipe, go to my Cakeculator and choose “Vanilla Swiss Meringue Buttercream."
- Set up the double boiler (bain-marie). Find a pot to hold a large metal bowl without touching the bottom. If you plan on whipping your egg whites, you can use the stand mixer bowl for this step. If not, use another metal bowl.
Fill the pot with water so the bowl is directly above but not touching the water. The closer the bowl is to the surface, the better, as this is where heating will be most efficient. Remove bowl for now and heat the water to a gentle simmer. - Heat the meringue syrup. Add the egg whites and sugar to your bowl and mix with a spatula; it will be viscous (gooey) and thick.
Once you see a steady fog rising from the surface of the water, place the bowl atop the pot. Continuously stir with the spatula, scraping down the sides to remove any sugar stuck on the sides. As the mixture heats, the eggs will thin out, the sugar will dissolve, and the mixture will become more opaque.
For fresh egg whites: use a thermometer to ensure you reach 160-165 °F (71-74 °C).
For liquid pasteurized egg whites from a carton: use your fingers to rub a bit of meringue carefully; once you no longer feel any sugar granules, your meringue is done.
Whip the meringue (optional). Whipping the meringue provides a minimal increase in aeration, so I usually skip this and move on to step 4. However, both preparations, meringue or syrup, must be cooled to the touch before adding the butter in the next steps. Use the whisk attachment and whip on high speed until it reaches stiff peaks. The timing will depend on the quantity of egg white mixture and powder in your stand mixer, but you’ll know it’s done when the meringue is very stiff and balls inside the whisk.
If for some reason (egg yolk contamination), you don’t get your meringue to whip, don’t worry. You can still proceed with this buttercream.
- Prepare the Frosting Butter. Add the slightly softened butter to the stand mixer bowl. With the whisk attachment, mix on high speed for about 2 minutes, scraping down the sides at least once. After mixing, the butter will be lighter in color, smooth, soft, and ball inside the whisk.
Add the powdered sugar, vanilla extract, and a small pinch of salt to the butter and whisk again on medium high speed for another 1-2 minutes.
If you used the stand mixer bowl to heat and whip your meringue, just move the meringue to another bowl for now, and you can use the stand mixer bowl to make the frosting butter. You don’t need to clean the bowl.
- Combine the meringue/syrup with the Frosting Butter. Add the syrup/meringue in 2 to 3 additions, mixing for about 30 seconds or until combined. Once all the syrup has been added, mix on high speed for an additional minute.
- Flavor and smooth the frosting: The whisk attachment introduced lots of air pockets, so switch over to the paddle attachment and mix on low speed for at least a few minutes to smooth out the frosting. Give the frosting a taste and adjust for vanilla and salt, if needed.
The final frosting should be ultra smooth and creamy.
Recipe Card - Adriana's Notes
*If you’re using fresh eggs, one large US egg contains around 28-33 g of egg whites. For example, a 3 cup quantity of frosting requires 121 grams of egg whites, so you’ll need about 4 eggs. Also, you may use pasteurized egg whites, which can be found in most grocery stores in cartons next to the fresh eggs. Please see the sections above for further explanation.
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