Lunchbox Cakes (Your complete guide)
I’ve baked tons of lunchbox cakes and have published videos about them on YouTube/Instagram/TikTok. Here is my complete lunchbox cake guide containing all my tips. Get ready to bake the cutest little cakes ever.
Lunchbox (or bento) cakes are mini cakes originating from South Korea. They are packaged and eaten inside takeout boxes, making them perfect for gifts. Each one contains small layers of cake that are stacked, frosted, and often decorated with messages or simple piping.
What exactly is a lunchbox cake?
Lunchbox cakes are a style of mini cake. The individual cake layers range in diameter from 3-4 inches (7.5-10 cm), though I have seen some that are larger. My lunchbox cakes contain two or three layers, which ends up being 4-5 inches (10-13 cm) wide after it’s frosted. The final height depends on the frosting design and what type of box I’ll use (which I’ll get to in a minute.)
Each of my two-layer cakes is equivalent to about 4 cupcakes, which is about 1-2 adult cake servings.
You can use any type of frosting, from buttercreams to whipped creams. The only design consideration that seems consistent with these cakes is their minimalist look. If you’re good at piping letters (I am not!), these cakes are adorable with little messages written on top.
Presentation-wise, these cakes are packaged in little takeout containers and sometimes include some candles or a spoon. The idea is that you can just sell these little cakes or gift them to friends as a whole package that can be eaten directly from the container.
What kind of cake do you need for lunchbox cakes?
As for the size of cakes, it’s a good idea to work backward if you already have a box.
That means taking a look at the interior size of your box. My boxes are 6-inch squares, so 4-inch cakes or smaller ones would do best. The cake size doesn’t include frosting, so that extra inch on the sides accounts for that.
And remember, you also want to account for the width of the cake and height. When the box closes, make sure there’s enough clearance that it won’t push on the designs you piped. This is another reason I typically only make two layers of cake for these mini cakes.
As for the type of flavor of cake, you can use any kind you like! If you want, I have many flavor options for you in my Cakeculator. One of the reasons I built the darn thing is that we don’t have to think about math and logistics when it comes to stuff like this.
But first, let’s go over how to get the size of cake we need for lunchbox cakes.
What pans do you need to make lunchbox cakes?
I use one of two types of pans to make my lunchbox cake layers: a sheet pan or use a silicone mold.
Bakers often ask me which method I prefer. Honestly, I use both, so here’s a comparison of both types of pans.
Sheet Pan Method
You can use a sheet pan of any size, but I like half-sheet pans. You’d bake a thin cake in a sheet pan and then use a round cutter or small bowl to cut out little cake circles. You can get lots of little cakes this way, but ultimately it will depend on your cutter size.
Advantages
- No special pans required
- Can cut any shape (hearts, circles of different sizes)
Disadvantages
- Lots of scraps (good if you make/sell other items like cakesicles or cake cups)
If you’re using the Cakeculator and want to make the half-sheet cake, choose any flavor you want and “Half-sheet pan.” This will bake up a thin cake layer in a half-sheet pan.
Silicone Mold Method
I bake enough of these mini cakes that I looked for a specific mold to bake cakes. I found one, and I love it - it’s a large baking mold with 6 holes that are precisely 4 inches in diameter.
And I love this mold - I use it for molding ice cream for mini ice cream cakes and baking brownies, and it’s just a good size for single-serving desserts.
Advantages
- perfectly flat layers of cake
- fewer cake scraps
- super-efficient - if I had a lunchbox cake business, this would give me the perfect result every time.
Disadvantages
- another baking pan to buy (though I use mine for brownies and ice cream patties for sandwiches too)
- doesn’t conduct heat as efficiently (no crispy sides and bottom of the cake)
If you have the silicone molds, you can choose any flavor you want, and for the pan size, select “4” mini cakes.” I have two options available - you can bake 6 layers or 12 layers.
How much frosting do you need?
A good rule that I follow for 4-inch mini cakes with 2 layers is that I allocate about 1 cup of frosting per cake. That’s usually plenty for piping any designs I have planned for the top.
You can use any frosting recipe in my Cakeculator. It will create a recipe with enough frosting when you choose any pan size.
What types of boxes do you need for lunchbox cakes?
In my older videos, I put these cakes in treat boxes, but they were so small they would slide around inside. Plus, you had to think about mini cake boards, which was a hassle.
Currently, I assemble and frost the lunchbox cakes on squares of parchment paper and place them in compostable takeout boxes. The boxes are from Amazon.
Step by step:
How to assemble lunchbox cakes
Step 1. Bake your mini cake layers and prep frosting.
Use either of my methods listed above to make the cake layers and frosting. In this tutorial I'm using my marble cake recipe baked in a silicone mold. The frosting is condensed milk buttercream.
Step 2. Cut squares of parchment.
The boxes I use are 6-inch squares, so I cut my squares a little smaller. It doesn’t have to be perfect, just big enough for you to lift up the cakes as needed. Place a schmear of frosting so the cake sticks.
Step 3. Fill and crumb coat your first cake.
Lay down your first layer. Add fillings, then your next layer.
Do a crumb coat all around. (A crumb coat is a super light layer of frosting that goes all around to lock in the crumbs)
Repeat with the rest of your cakes, then place them in the fridge to chill.
Step 4. Apply the top coat of frosting
The top coat is a thicker layer that goes all around the cake and can be as thin or thick as you like.
Step 5. Prep frosting for piping.
While the cakes are chilling, I make the frosting colors and prepare the piping bags and tips for the design I have planned for the top. You can do this ahead of time too, I just like to frost my cakes first so I know how much left I have to work with for the piping.
Here's a cool tip - I use a web app to pick colors for my cakes. (Do you see I'm trying to match the colors on my phone in the corner of the pic?) I'm pretty bad at matching colors for a palette but I can tell when something looks good. So I use the Coolors app to scan through various palettes and then do my best to match it using food coloring. I'm using oil-based coloring here but gel food coloring works well too.
Step 6. Pick up the cake using the parchment and place the cake inside the box.
It’s much easier to decorate once it’s in the box. And don’t worry about the sides. It’s understood that these cakes will rub a little against the parchment, and the sides shouldn’t have any decorations.
Step 7. Pipe your designs on top.
Now it’s your time to be creative!
Lots of bakers like to write cute messages on their cakes. Or maybe a celebratory message to whoever the lucky person will get this cake.
Now you can close the box, tie it with a bow, and gift them out! This is such a cute project to do with kids too. Once you have everything all baked up, the kids can use frosting, piping tips, and sprinkles to make their own little cakes. I've done it a few times already and every time the kids have loved it.
Video
I have a video tutorial on how to bake and remove the cake in a pan of this size.
I have a bunch of videos on lunchbox cakes on my channel and here's a vid I made compiling more tips like freezing little cakes:
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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