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Chocolate Bento Cake - A Tiny Cake With Big Flavor

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Prep Time 20 minutes
Cook Time 25 minutes
Total Time 45 minutes
Servings: 4 servings
Ingredients Method

Ingredients
  

  • For the Cake (4–5 inch, two layers):
  • 3/4 cup (95 g) all-purpose flour
  • 1/4 cup (25 g) unsweetened cocoa powder, preferably Dutch-process
  • 1/2 cup (100 g) granulated sugar
  • 1/4 cup (50 g) light brown sugar, packed
  • 1/2 tsp baking soda
  • 1/2 tsp baking powder
  • 1/4 tsp fine salt
  • 1 large egg, room temperature
  • 1/3 cup (80 ml) buttermilk, room temperature
  • 1/4 cup (60 ml) neutral oil (canola or vegetable)
  • 1 tsp vanilla extract
  • 1/3 cup (80 ml) hot brewed coffee or hot water
  • For the Chocolate Buttercream:
  • 1/2 cup (115 g) unsalted butter, softened
  • 1 1/2 cups (180 g) powdered sugar, sifted
  • 1/4 cup (25 g) unsweetened cocoa powder
  • 2–3 tbsp heavy cream or milk
  • 1 tsp vanilla extract
  • Pinch of salt
  • Optional for Assembly and Decoration:
  • Simple syrup (1 tbsp sugar + 1 tbsp hot water) for brushing
  • Sprinkles, chocolate shavings, or a small message piped in white chocolate
  • Parchment paper and a 4–5 inch bento box or small cake box

Method
 

  1. Prep the pans: Grease and line two 4- or 5-inch round cake pans with parchment. Preheat your oven to 350°F (175°C). If you only have one pan, bake in two batches.
  2. Mix dry ingredients: In a medium bowl, whisk flour, cocoa powder, granulated sugar, brown sugar, baking soda, baking powder, and salt until well combined.
  3. Combine wet ingredients: In a separate bowl, whisk the egg, buttermilk, oil, and vanilla until smooth.
  4. Bring it together: Add the wet mixture to the dry ingredients. Stir gently until just combined. Don’t overmix.
  5. Add the hot liquid: Pour in the hot coffee (or hot water). Stir until the batter is smooth and slightly thin. This step deepens the chocolate flavor.
  6. Bake: Divide the batter between the pans. Bake for 18–22 minutes, or until a toothpick comes out with a few moist crumbs. Small cakes bake fast, so keep an eye on them.
  7. Cool completely: Let the cakes rest in the pans for 10 minutes, then turn onto a rack to cool. Wrap and chill for 30 minutes for easier assembly.
  8. Make the buttercream: Beat butter until creamy and pale, about 2 minutes. Sift in powdered sugar and cocoa. Add vanilla, salt, and 2 tbsp cream. Beat on medium-high until fluffy. Add more cream if needed for a silky, spreadable consistency.
  9. Level and prep: If the cake tops are domed, level them with a serrated knife. If using simple syrup, lightly brush each layer to keep it extra moist.
  10. Layer the cake: Place one layer on a small board or parchment square. Spread a generous layer of buttercream on top. Set the second layer over it.
  11. Crumb coat: Apply a thin layer of frosting all over to seal in crumbs. Chill 10–15 minutes.
  12. Final coat and decorate: Smooth on a thicker coat of buttercream. For the bento look, keep the sides neat and the top flat. Add sprinkles, pipe a short message, or finish with chocolate curls.
  13. Box it up: Line your bento box with parchment. Gently transfer the cake into the box. Keep chilled until it’s time to serve or gift.