Chocolate Sponge Cake with Buttercream
Filling: A Decadent Delight
Ingredients
For the Sponge Cake:
- 8 egg whites
- 220 g sugar (granulated)
- 75 g all-purpose flour
- 50 g cocoa powder (unsweetened)
For the Buttercream Filling:
- 8 egg yolks
- 50 g sugar
- 10 g vanilla sugar (or vanilla extract to taste)
- 70 g all-purpose flour
- 100 ml milk
- 200 g butter (softened)
Other:
- Vegetable oil (for greasing the pan)
How to Make Chocolate Sponge Cake with Buttercream Filling
Step 1: Prepare the Sponge Cake Batter
Separate the Eggs: Carefully divide the egg whites and yolks into two separate bowls. Ensure no yolk contaminates the whites, as it can prevent the whites from whipping properly.
Whip the Egg Whites: Using a mixer, beat the egg whites on medium speed until fluffy. Gradually add the sugar, one tablespoon at a time, while continuing to beat. Increase the speed to high and beat until stiff peaks form. The mixture should be glossy and smooth, with no sugar granules remaining.
Sift the Dry Ingredients: In a separate bowl, sift the flour and cocoa powder together to remove lumps.
Fold in the Dry Ingredients: Gradually add the flour and cocoa powder mixture to the beaten egg whites, folding gently with a spatula. Be careful not to deflate the airy batter.
Step 2: Bake the Sponge Cake
- Preheat your oven to 180°C (356°F).
- Grease your baking pan or silicone mold with vegetable oil to prevent sticking.
- Pour the batter into the prepared pan, smoothing the top with a spatula.
- Bake for 25–30 minutes or until a toothpick inserted in the center comes out clean.
- Remove the cake from the oven and allow it to cool completely. Level the top of the cake with a knife if needed and cut it into two even layers.
Step 3: Prepare the Buttercream Filling
Combine Ingredients: In a medium saucepan, whisk together the egg yolks, sugar, vanilla sugar, flour, and milk until smooth.
Cook the Mixture: Place the saucepan over medium heat and cook the mixture, stirring constantly, until it thickens. This step requires patience and vigorous stirring to prevent lumps.
Cool the Cream Base: Transfer the thickened mixture to a bowl and beat with a mixer for 3-5 minutes until it cools completely.
Incorporate the Butter: Gradually add softened butter to the cooled cream base, beating continuously until the mixture is smooth and fluffy. The buttercream should hold its shape and have a silky texture.
Step 4: Assemble the Cake
Place one layer of the sponge cake on a serving plate. Spread a generous layer of buttercream evenly over the surface.
Top with the second layer of sponge cake and press gently to secure. Spread the remaining buttercream over the top and sides of the cake for a smooth finish.
Decorate the cake as desired. You can sprinkle cocoa powder, grated chocolate, or fresh fruit for a decorative touch.