The Cutest Little Bento Cake Recipe

This bento cake recipe makes 6 adorable mini Korean-style cakes with fluffy vanilla buttercream — perfect for gifting, celebrating, and making someone’s whole day.

The Quick Answer: What Is a Bento Cake?

A bento cake is a charming, single-serving mini Korean cake — typically 4 inches wide — built from tender sheet cake layers soaked in simple syrup, stacked with silky vanilla buttercream frosting made from unsalted butter, heavy cream, and powdered sugar, then tucked into a little takeout-style box and decorated with piped messages or sprinkles.

Okay, real talk — the first time I saw a bento cake, I actually thought it was a prop from a drama. It was that cute. These little Korean-style mini cakes started trending out of Seoul’s café culture, and once they hit my feed, I knew I had to figure them out in my own kitchen.

I tested this small bento cake recipe more times than I care to admit (my coworkers were very happy about that), and I finally landed on a version that’s approachable, genuinely delicious, and so satisfying to gift.

If you love the idea of adorable, individually-sized celebration cakes, you’re going to want to bookmark our ultimate guide to celebration cakes too — it pairs beautifully with everything you’ll learn here.

Why You’ll Love This Bento Cake Recipe

Let me count the ways, friend.

It’s ridiculously gift-worthy. A mini bento cake slipped into its little box with a handwritten note? That is the gift. No wrapping paper needed.

The vanilla buttercream is a dream. We’re talking Kerrygold butter, real vanilla extract, and heavy whipping cream whipped together into something that tastes like a cloud decided to be delicious. I’ve made a lot of frostings, and this one converted me.

You don’t need fancy skills. If you’ve ever frosted a cupcake, you can make this korean bento cake. The box hides any imperfections anyway — it’s the most forgiving little cake format I’ve ever worked with.

It’s endlessly customizable. Chocolate cake mix, lemon, funfetti — swap it out and the whole vibe changes. Write a name in gel frosting, add sprinkles, go wild with piping tips. It’s your tiny canvas.

I remember the first batch I brought to a birthday lunch. My friend literally gasped when she opened the little box. Gasped. For a cake I made in a sheet pan. These have real magic in them.

For more birthday inspiration, don’t miss our happy birthday cupcake recipe guide — it’s another crowd-pleaser that pairs perfectly with this bento cake aesthetic.

Nutritional Peek (Per Serving)

Nutrient	Per Serving
Calories	~480 kcal
Total Fat	27g
Carbohydrates	56g
Protein	3g
Sugar	42g

Note: Nutritional values are estimates based on standard cake mix and full frosting. Values vary depending on the cake mix brand and decoration choices.

What Do You Need to Make a Mini Bento Cake?

This small bento cake recipe keeps the ingredient list refreshingly simple — nothing wild, nothing you’d have to order from a specialty shop. A quality box cake mix does the heavy lifting on the cake itself, so you can pour your energy into that dreamy vanilla buttercream.

I truly swear by Kerrygold butter for frosting. It has a slightly higher fat content than most American butters, and the flavor difference is noticeable — richer, creamier, more luxurious. It’s one of those small upgrades that makes a big difference.

Ingredients Table

Servings: 6 mini bento cakes

Amount	Ingredient	Notes
1 box (15–22 oz)	Prepared cake mix	Any flavor you love — funfetti is a crowd favorite!
2 tsp	Simple syrup	This keeps your layers moist and tender
1 cup	Unsalted butter, room temperature	Kerrygold is my personal ride-or-die here
1 tsp	Vanilla extract	Pure extract, not imitation — it shows
2⅔ cups	Powdered sugar	Sifted if you want extra-smooth frosting
½ cup	Heavy whipping cream, room temperature	Room temp is key — cold cream can make frosting grainy
As needed	Sprinkles	Optional, but honestly… always
As needed	Gel frosting	Optional — perfect for writing sweet messages

What Equipment Will I Need?

Here’s what you’ll want to gather before you start:

• 12×17 inch half sheet pan (jelly roll pan) — this is your cake base
• Parchment paper — you’ll use quite a bit, so grab a good roll
• Cooking spray — for easy release
• Stand mixer or hand mixer with paddle attachment
• 6-inch circle biscuit or cookie cutter — the key to your perfect little cake rounds
• Wire cooling rack
• Offset spatula or bench scraper — for smooth, clean frosting
• Piping bags and various tips — for decorating
• Bento cake boxes (6 of them!) — find these on Amazon or at Korean stationery shops
• Butter knife — for loosening cake edges

How Do You Make a Bento Cake Step by Step?

Making a bento cake is one of those projects that feels like a whole experience — a little project, a little creativity, and a whole lot of reward at the end. Let’s walk through it together.

Preparing the Cake

1. Preheat your oven to 350°F. Spray your 12×17 inch half sheet pan generously with cooking spray, then press a sheet of parchment paper down into it — make sure it covers the bottom fully, pushes into the corners, and comes up the sides a little. This step saves you from a stuck cake disaster later, so don’t rush it.

2. Prepare your cake mix batter according to the box directions, then pour it all into your prepared pan. Use an offset spatula to spread the batter as evenly as you possibly can — an even layer means even layers in your finished cakes, which makes stacking much easier.

3. Bake for 20–24 minutes, until the top is golden and a toothpick inserted in the center comes out clean with no wet batter. Let it cool completely before you try to cut it — I know waiting is hard, but a warm cake crumbles and your circles won’t hold their shape.

4. Run a butter knife around the entire edge of the pan to loosen the cake. Place a piece of parchment paper on top of the cake, then a wire cooling rack, and in one confident motion — flip the whole thing. The cake should release cleanly onto the rack. (If it doesn’t, give the bottom of the pan a few gentle taps.)

Making the Vanilla Buttercream Frosting

5. Add your room-temperature Kerrygold butter to your stand mixer with the paddle attachment. Beat on medium speed for about 30 seconds until it’s smooth and creamy, then add the vanilla extract and mix on low until fully incorporated. The butter should look pale and fluffy at this point.

6. Start adding the sifted powdered sugar slowly — about ½ cup at a time. When you’ve added 1½ cups, pause and pour in the room-temperature heavy whipping cream. This is the moment the frosting transforms — it’ll go silky and luscious. Add the remaining powdered sugar and continue mixing on low until everything is fully combined, smooth, and cloud-like.

Assembling Your Bento Cakes

7. Use your 6-inch circle cutter to cut 12 even circles from your cooled sheet cake. You should get plenty — arrange them on the wire rack as you go. Cut four 9-inch squares of parchment paper and set them aside; these are your little frosting stations.

8. Place one parchment square on your work surface and add just a tiny smear of buttercream to the center — this acts like glue and keeps your first cake layer from sliding around. Press the first cake circle on top, then drizzle it with 1 teaspoon of simple syrup. (The simple syrup soaks into the cake and keeps it moist and tender — don’t skip this step!)

9. Spread an even layer of vanilla buttercream over that first cake circle, smoothing it out with your offset spatula. Keep the layer consistent so your finished cake sits level.

10. Place the second cake circle on top of the frosted layer and drizzle with another teaspoon of simple syrup. Now apply a thin crumb coat all over the outside of the cake — top and sides — using your spatula or scraper. This thin layer traps any crumbs so your final coat looks clean. Repeat until all 6 cakes are assembled.

11. Pop all the cakes into the freezer for 10 minutes until that crumb coat is firm to the touch. Remove them, apply a thicker, more generous layer of vanilla buttercream all over each cake, and smooth as much as you’d like. Return them to the freezer for another 10 minutes to set that final coat.

12. Carefully lift each finished cake using the parchment paper underneath and lower it gently into its bento box. Now for the fun part — divide the remaining buttercream into small portions, tint with gel food coloring if you’d like, fill piping bags fitted with your favorite tips, and decorate!

Write names, pipe little hearts, add sprinkles — this is where your personality gets to shine. Gel frosting tubes or sugar letter decorations also work beautifully for writing messages.

Pro Tips for the Perfect Mini Bento Cake

Use room-temperature ingredients — always. Room-temperature butter and heavy cream incorporate together far more evenly, creating a stable, smooth emulsion.

According to King Arthur Baking, cold butter doesn’t whip to the same light, airy texture, and cold cream can actually cause your frosting to curdle or look curdled. Take your butter and cream out at least an hour before you start.

Don’t skip the simple syrup. Sheet cake baked in a thin layer can dry out quickly once cut. That drizzle of simple syrup on each layer is what keeps your korean bento cake tasting moist and bakery-fresh, even hours after you’ve assembled it. It’s a small step that makes a big difference.

Freeze between layers — really. I know it feels impatient to keep putting cakes in the freezer, but those 10-minute chills are what make clean, sharp-edged bento cakes possible. Frosting that hasn’t set slides and smears. Chilled frosting behaves beautifully.

Use a 6-inch cutter — not a knife. A circle cutter gives you clean, uniform edges. A knife freehand? You’ll end up with lopsided cakes that don’t stack properly. Invest in a set of biscuit cutters — they’re inexpensive and useful for so much more than bento cakes.

Gel food coloring over liquid. For tinting your decorating buttercream, gel food coloring gives vibrant, saturated color without adding extra liquid to your frosting. Liquid food dye can make your frosting too soft and runny.

Troubleshooting Your Bento Cake

Why does my buttercream look grainy or curdled?
This almost always comes down to temperature. If your butter was too cold or your heavy cream was straight from the fridge, the fat molecules don’t emulsify properly. No worries — try gently warming the outside of the mixing bowl with your hands or a warm towel and then beat again. It usually comes right back together.

Why did my cake crack when I cut the circles?
The cake wasn’t completely cool, or it dried out slightly during cooling. Make sure your cake is fully cooled to room temperature before cutting, and work quickly once it’s flipped. A slightly warm cake tears easily under a cutter.

What if my crumb coat is full of gaps and crumbs?
That’s totally fine and completely normal — it’s literally called a crumb coat for a reason! The whole point is to trap those crumbs in a thin layer so they don’t appear in your final frosting. Just make sure it’s chilled and firm before you apply the final coat.

Why does my frosting slide off the sides?
Your frosting is probably too warm, or the cake layers are still releasing warmth. After assembling, that first 10-minute freeze is critical. If the problem persists, chill your frosting bowl briefly before applying the final coat.

What if I can’t find bento boxes?
Look on Amazon for “bento cake boxes” or “mini cake boxes” — they’re widely available. Korean convenience stores or Asian grocery stores often stock them too. In a pinch, small takeout containers with lids work just as well and honestly add a charming rustic feel.

Variations & Twists on This Bento Cake Recipe

One of my favorite things about this bento cake recipe is how endlessly flexible it is. The base technique stays the same — you’re really just swapping the flavor profile.

Chocolate Korean Bento Cake: Use a devil’s food or dark chocolate cake mix and swap the vanilla buttercream for a chocolate version by adding ¼ cup of unsweetened cocoa powder. Top with chocolate shavings or mini chocolate chips for extra drama.

Lemon Bento Cake: Use a lemon cake mix and add 1 tablespoon of fresh lemon zest to your buttercream. Dust the tops with powdered sugar and a few candied lemon slices for a bright, sunny look.

Strawberry Bento Cake: Use a strawberry cake mix and fold 2 tablespoons of strawberry jam into a portion of your buttercream for filling. Fresh strawberry slices between the layers make it look stunning when you cut in.

Funfetti Birthday Bento Cake: Use a funfetti mix, add extra rainbow sprinkles into the buttercream itself, and pipe a birthday message on top. It’s pure, unfiltered joy in a box.

For a truly show-stopping alternative, our burn away cake recipe is another incredibly fun option if you want to add some theatrical flair to a celebration spread alongside these little bento beauties.

Serving, Storage & Reheating

Serving: These mini bento cakes are best served at room temperature — take them out of the fridge (or bento box) about 20–30 minutes before serving so the buttercream softens back to that creamy, melt-in-your-mouth texture. Cold buttercream is a little dense and waxy, and nobody deserves that.

Storage: Store assembled bento cakes in their boxes in the refrigerator for up to 3 days. The simple syrup keeps the layers from drying out, so they stay lovely throughout. Keep the lid closed to prevent the cake from absorbing any fridge odors.

Freezing: You can freeze fully assembled, unfrosted cake rounds (wrapped tightly in plastic wrap) for up to 2 months. Thaw overnight in the fridge, then assemble and frost. I wouldn’t recommend freezing the fully decorated cakes — the gel frosting and decorations don’t always survive the freeze-thaw cycle looking their best.

Reheating: These aren’t really a “reheat” situation — they’re a cake, not a casserole! If your slice feels a little firm straight from the fridge, just let it sit at room temperature for 15–20 minutes. It’ll come back to life perfectly.

No-Waste Kitchen Magic

Sheet cake baking always leaves behind some scraps — those odd-shaped bits of cake left after you punch out your circles. Here’s how to give them a second life:

• Cake crumble topping: Crumble the scraps and toast lightly in a 300°F oven for 10 minutes — they become a crispy, delicious topping for ice cream or yogurt parfaits.
• Cake pops: Mix scraps with a little leftover buttercream until a soft dough forms, roll into balls, and dip in melted chocolate. Instant cake pops.
• Trifle layers: Layer cake scraps in a glass with whipped cream and fresh berries for a stunning fridge dessert that takes about 5 minutes to throw together.
• Snacking: Honestly, standing over the counter eating cake scraps while your bento cakes chill is a legitimate chef’s privilege. Highly recommended.

Frequently Asked Questions About Bento Cakes

Ready to Make the Most Adorable Cakes of Your Life?

There’s something so genuinely joyful about tucking a little decorated bento cake into a box and handing it to someone you love. It’s personal in a way that a grocery store cake just… isn’t. Whether you’re making your first small bento cake for a friend’s birthday or you’re planning a whole set of six for a party, I really think this recipe is going to become a regular in your kitchen.

Drop a comment below and tell me what flavor combination you tried — or better yet, share your photos! I love seeing how everyone puts their own spin on these. And if you’re in a celebratory baking mood, don’t miss our ultimate celebration cake guide for even more inspiration.

Happy baking, friend.

Baked with love by Rebeccah Ellene.