Bento Cake Recipe: Easy Mini Lunchbox Cakes with 3 Cute Designs
This bento cake recipe and all the photos come from Thy Than, a baker whose lunchbox cake video has been watched more than 3.5 million times on YouTube. Follow her on Instagram at @thythan_recipes.
Bento cakes, also called lunchbox cakes, are mini cakes about 4 inches wide, packed in a small takeout box. They come from Korea and became a favorite for birthdays, anniversaries and small gifts, because they’re just big enough for one or two people and cute enough to say it all with a short piped message.
This bento cake recipe makes 3 mini cakes from a single chocolate sheet cake: you bake one thin cake, cut out 9 rounds and stack them in 3 layers with a light vanilla buttercream. Then you decorate them in three styles: dusty pink with love you, sage green with happy day and a blue ombré with happy holiday.
Table of Contents
Why you’ll love this bento cake recipe
- No special pans: one sheet pan and a round cutter replace three tiny cake tins.
- 3 cakes, 3 designs from one batch, perfect for gifts or a small party.
- A moist chocolate cake with coffee and hot water for deep cocoa flavor.
- Easy, stable buttercream that colors well and holds piped borders and letters.
Bento cake size: how big is a bento cake?
A classic bento cake is about 4 inches (10 cm) wide and 3 to 4 inches tall, enough for 1 to 2 people. In this recipe the layers are cut at 8 cm (3 inches) and end up about 10 cm wide once frosted.
| Layer size | Frosted cake | Serves |
|---|---|---|
| 8 cm / 3 inches | about 10 cm / 4 inches | 1 to 2 people |
| 10 cm / 4 inches | about 12 cm / 5 inches | 2 to 3 people |
| 15 cm / 6 inches | about 17 cm / 7 inches | 4 to 6 people |
Ingredients for this bento cake recipe
For the chocolate cake
- Flour, cocoa powder, baking soda and baking powder: the cake is light but sturdy enough to stack.
- Instant coffee and hot water: they bring out the chocolate flavor; the cake doesn’t taste of coffee.
- Brown or white sugar: brown sugar makes it a little moister.
- Egg, milk, melted butter (or oil), vanilla and vinegar: the vinegar reacts with the baking soda for a tender crumb.
For the vanilla buttercream
- Unsalted butter at room temperature: soft enough to whip pale and fluffy.
- Powdered sugar: about 150 g, adjust to how sweet you like it.
- Heavy cream: added a spoonful at a time for a smooth, pipeable texture.
- Gel food coloring: pink, green and blue, plus a touch of brown and black for the sage green.
Tools
- A 22 x 36 cm (9 x 14 inch) sheet pan and an 8 cm (3 inch) round cutter
- An offset palette knife, a cake scraper and a turntable
- Piping bags with Wilton tips #2 (writing), #6 and #21 (borders) and #32
- Paper burger boxes or bento cake boxes
How to make a bento cake: step-by-step bento cake recipe
1. Make the chocolate sheet cake
Sift the flour, cocoa, baking soda, baking powder, salt and coffee, then whisk in the sugar. Add the egg, milk, melted butter, hot water, vanilla and vinegar and whisk until smooth.
Pour into the lined pan, spread evenly and bake at 180°C (350°F) for 20 to 25 minutes. Let it cool completely.
2. Cut the layers
Peel off the parchment and cut out 9 rounds with an 8 cm cutter: 3 layers for each cake.
3. Make the vanilla buttercream
Whip the butter until pale and fluffy, scraping the bowl often. Add the powdered sugar and vanilla, then the cream 1 tablespoon at a time. Finish by stirring by hand to push out big air bubbles; it makes smoother sides, the secret of any good bento cake recipe.
4. Stack and crumb coat
Brush each layer with a little sugar syrup to keep it moist, spread a layer of buttercream and repeat until you have 3 layers. Cover with a thin crumb coat and chill for about 10 minutes.
5. Color the buttercream
Divide the rest of the buttercream into 4 bowls: keep one white and tint the others dusty pink, sage green and blue.
6. Cover and smooth
Cover the lower part of the cake first, then the top. Hold the scraper still against the side while you turn the turntable, fill any holes and smooth again. Clean the palette knife after each pass for a sharp top edge.
7. Pipe the border and write the message
Pipe a border around the top edge, then write your message in white buttercream with tip #2.
Bento Cakes (Chocolate Cake with Vanilla Buttercream)
Ingredients
Method
- Preheat the oven to 180°C (350°F) and line a 22 x 36 cm (about 9 x 14 inch) sheet pan with parchment paper.
- Sift the flour, cocoa powder, baking soda, baking powder, salt and coffee powder into a bowl. Add the sugar and whisk to combine.
- Add the egg, milk, melted butter, hot water, vanilla and vinegar, and whisk until the batter is smooth.
- Pour the batter into the pan and spread it evenly. Bake for 20 to 25 minutes, until a toothpick comes out clean. Let it cool completely.
- Cut out 9 rounds with an 8 cm (3 inch) round cutter: 3 layers for each of the 3 cakes.
- For the buttercream, whip the butter until pale and fluffy, scraping the bowl often. Add the powdered sugar and vanilla, then the heavy cream about 1 tablespoon at a time, mixing until incorporated. Finish mixing by hand to remove big air bubbles.
- Brush a cake round with a little sugar syrup, spread a layer of buttercream, and repeat until you have 3 layers. Cover the cake with a thin crumb coat. Repeat for the other 2 cakes and chill them for about 10 minutes.
- Divide the remaining buttercream into 4 bowls: keep one white and tint the others dusty pink, sage green and blue.
- Cover each cake with its color, smoothing the sides with a scraper while turning the cake and the top with a clean palette knife.
- Decorate: pipe borders with tips #6 or #21 and write the message in white buttercream with tip #2. Chill until firm, then place each cake on parchment in a burger box.
Notes
3 bento cake designs from the video
Dusty pink “love you” cake
Cover the cake in dusty pink, then lighten some of the cream with extra white and pipe a shell border with tip #6. Write love you in white with tip #2.
Sage green “happy day” cake
Cover the cake in sage green, pipe a ruffled border with the leftover pink cream and tip #21, then write happy day in white. Pink and green make a soft, pretty contrast.
Blue ombré “happy holiday” cake
Spread white cream on top and blue on the sides, add a little extra white on the sides and smooth with the scraper for an ombré effect. Add a patch of blue in the center of the top, write happy holiday in white and finish with small buttercream dots.
Watch the video
More bento cake design ideas
Minimalist bento cake
One pastel color, a smooth finish, a thin border and a short message: happy birthday, a name or a date. Minimalist designs are the easiest way to start and always look neat.
How to decorate a bento ribbon cake
Ribbon bento cakes, decorated with piped bows, are one of the most popular styles. Use a stiff buttercream so the bows hold their shape and a small petal tip (such as Wilton 104) for flat, ribbon-like loops, or a small round tip for thin, delicate bows. Pipe two loops that meet in the center, two short tails, and a dot for the knot. Place one large bow on top or small bows around the side, and tie a real satin ribbon around the box for a gift-ready look.
Fruit bento cake
Top a white or pale pink cake with a few strawberries, blueberries or kiwi slices just before serving, and pipe a simple border to frame the fruit. Pat the fruit dry so it doesn’t bleed into the buttercream.
Vintage and aesthetic bento cakes
For the vintage look, pipe layered shell and ruffle borders (tips #21 and #32) in two shades of the same color, add buttercream dots or small cherries, and keep the palette soft: blush, cream, lilac, sage.
Simple drawings and birthday bento cakes
With tip #2 you can draw a tiny heart, a smiley, a cat face or a candle instead of words. For a birthday, write the age in big numbers and add a single candle.
Want an all-chocolate version? See our chocolate bento cake.
Tips for this bento cake recipe
- Let the cake cool completely before cutting the rounds, or they will tear.
- Chill between steps. 10 minutes in the fridge after the crumb coat makes smoothing much easier.
- Practice your lettering on parchment first, and pipe with steady pressure, holding the tip just above the surface.
- Use gel coloring, which colors without thinning the buttercream. Colors deepen as they rest.
- Keep the top flat: place the last layer upside down so the smooth bottom is on top.
How to store and transport bento cakes
Place each cake on a square of parchment and slide it into a paper burger box: it’s the right size and keeps the cake from moving. Keep the cakes in the fridge for up to 3 days, and take them out 30 minutes before eating so the buttercream softens. You can bake and freeze the cake rounds, well wrapped, up to 1 month ahead.
FAQ
What is a bento cake?
A small Korean-style cake, about 4 inches wide, sold in a takeout box. Bento cakes usually have a simple pastel design and a short piped message.
What size is a bento cake?
Usually 4 inches (10 cm) wide once frosted. Here the layers are cut at 8 cm (3 inches).
How many people does a bento cake serve?
One or two people. This bento cake recipe makes 3 cakes, so you can keep one and gift two.
Can I make this bento cake recipe ahead?
Yes. Bake the cake up to a month ahead and freeze it, or decorate the cakes the day before and keep them in the fridge.
How do I write on a bento cake?
Use a stiff white buttercream and a small round tip (#2). Chill the cake first so the surface is firm, and practice the words on parchment before piping on the cake.
Can I use whipped cream instead of buttercream?
Buttercream is better for bento cakes: it holds sharp edges and piping, and travels well in a box. Whipped cream is softer and needs to stay cold.
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