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

1. 1. 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.

1. 1. 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.
   2. Sift the Dry Ingredients: In a separate bowl, sift the flour and cocoa powder together to remove lumps.
   3. 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

1. 1. Preheat your oven to 180°C (356°F).
   2. Grease your baking pan or silicone mold with vegetable oil to prevent sticking.
   3. Pour the batter into the prepared pan, smoothing the top with a spatula.

1. Bake for 25–30 minutes or until a toothpick inserted in the center comes out clean.
2. 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

1. 1. Combine Ingredients: In a medium saucepan, whisk together the egg yolks, sugar, vanilla sugar, flour, and milk until smooth.

1. 1. 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.
   2. Cool the Cream Base: Transfer the thickened mixture to a bowl and beat with a mixer for 3-5 minutes until it cools completely.
   3. 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

1. 1. Place one layer of the sponge cake on a serving plate. Spread a generous layer of buttercream evenly over the surface.
   2. 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.
   3. Decorate the cake as desired. You can sprinkle cocoa powder, grated chocolate, or fresh fruit for a decorative touch.

Step 5: Serve

Allow the assembled cake to chill in the refrigerator for 30 minutes before serving. Slice and enjoy!

Tips for Making the Perfect Chocolate Sponge Cake

1. 1. Room Temperature Eggs: Use room-temperature eggs for better volume when whipping the whites.
   2. Sift Dry Ingredients: Sifting the flour and cocoa powder ensures a lump-free batter and a lighter texture.

1. 1. Gentle Folding: Avoid over-mixing when combining the dry ingredients with the egg whites to retain the batter’s airiness.
   2. Butter Consistency: Use softened butter for the buttercream to achieve a smooth and creamy texture.
   3. Chill Before Slicing: Refrigerating the cake for a short time makes it easier to slice cleanly.

Nutrition Facts (Per Serving)

• • Calories: 350 kcal
  • Protein: 7 g
  • Carbohydrates: 28 g

• • Fat: 23 g
  • Fiber: 1 g
  • Sodium: 150 mg

FAQs

1. Can I make this cake gluten-free?
Yes, substitute the all-purpose flour with a gluten-free flour blend designed for baking.

2. Can I use store-bought buttercream?
While homemade buttercream tastes fresher and richer, store-bought can be used for convenience. Adjust sweetness to your preference.

3. How can I ensure my sponge cake doesn’t deflate?
Be gentle when folding the dry ingredients into the whipped egg whites, and avoid over-mixing.

4. Can I add flavor to the buttercream?
Absolutely! Add a tablespoon of cocoa powder, melted chocolate, or coffee to the buttercream for a flavor twist.

5. How do I store leftover cake?
Wrap the cake tightly in plastic wrap or store in an airtight container in the refrigerator for up to 3 days.

Storage Tips

1. 1. Refrigeration: Store the cake in the refrigerator to maintain freshness. Cover it with plastic wrap or place it in an airtight container.

1. Freezing: You can freeze individual slices or the whole cake for up to 3 months. Thaw overnight in the refrigerator before serving.
2. Room Temperature: If serving within a few hours, the cake can be kept at room temperature, but avoid leaving it in a warm environment.

Why This Recipe is a Classic

The Chocolate Sponge Cake with Buttercream Filling combines lightness and richness, making it a beloved dessert worldwide. Its versatility allows it to be the centerpiece of celebrations or a comforting homemade treat. With a simple list of ingredients and straightforward techniques, this recipe can be passed down through generations.

This timeless dessert also invites creativity. You can customize the flavors, decorations, or even the filling to suit any occasion. Its enduring popularity lies in its ability to evoke nostalgia while remaining adaptable to modern tastes.

Conclusion

Creating a Chocolate Sponge Cake with Buttercream Filling is more than just baking; it’s crafting a dessert that brings joy and indulgence to any occasion. The fluffy sponge cake, paired with the creamy richness of buttercream, offers a perfect balance of texture and flavor.

This recipe not only delivers a delicious dessert but also serves as a reminder of the joy of sharing food with loved ones. Whether it’s for a birthday, holiday, or a quiet evening at home, this cake is a testament to the magic of baking. Prepare it with care, share it with pride, and savor every bite of this timeless treat.