Chocolate cake

1. Preheat your oven to 330°F (165°C) and line two 6-inch (15 cm) round cake pans with parchment paper.
2. In the bowl of a stand mixer fitted with the whisk attachment, add the eggs, granulated sugar, and vanilla extract. Beat on medium-high speed for at least 10 minutes, until the mixture becomes pale, fluffy, and triples in volume.
3. While that’s mixing, sift together the dry ingredients: cake flour, unsweetened cocoa powder, baking soda, baking powder, and salt.
4. Reduce the mixer speed to low and gradually add the dry ingredients. Mix for no more than 1 minute—just until combined.
5. In a separate bowl, whip the cold heavy cream using a hand mixer until it forms stiff peaks.
6. Add a small amount of the whipped cream to the batter and mix on medium speed just to loosen it a bit.
7. Then gently fold in the remaining whipped cream using a spatula, making sure to scrape the bottom of the bowl to fully incorporate everything.
8. Divide the batter evenly between the two prepared pans.
9. Bake for about 1 hour. To check for doneness, insert a toothpick into the center—it should come out clean.
10. Let the cakes cool slightly in the pans, then carefully remove and place them upside down on a wire rack to cool completely.
11. Once cooled, wrap each cake in plastic wrap and refrigerate for at least 2 hours. (You can also make the sponge 1 to 2 days ahead.)

Kinder chocolate ganache

1. Place the chopped chocolate and Kinder Maxi pieces in a heatproof bowl.
2. In a small saucepan, heat the heavy cream until it just starts to boil. Pour it over the chocolate and Kinder, then let sit for a minute before stirring until completely melted and smooth. Use an immersion blender if needed to get a silky texture.
3. Transfer the ganache to a container, cover with plastic wrap touching the surface, and refrigerate overnight.
4. The next day, whip the chilled ganache on medium speed for 3 to 5 minutes until slightly thickened.
5. Add the cold mascarpone and continue whipping for another 3 to 5 minutes until smooth and fluffy.
6. Keep refrigerated until ready to assemble the cake.

White chocolate Swiss meringue buttercream

1. Follow the recipe for White Chocolate Swiss Meringue Buttercream and leave at room temperature until ready to assemble.

Chocolate glaze

1. Place the chopped chocolate and heavy cream in a small bowl.
2. Heat in the microwave or double boiler until you have a liquid ganache.
3. Use the pouring glaze at 30-35°C (prepare it about 20 minutes before decorating)

Assembly, smoothing and decoration

1. Cut your sponge cake in 4 layers with a cake leveler or a large knife.
2. Fill 2 pastry bags with the buttercream and the other with the Kinder ganache.
3. Place the first layer on a cake turntable and place a curl of buttercream on the edges.
4. Fill the inside with ganache and add a few pieces of Kinder Bueno, add another layer of ganache and smooth with an angled spatula.
5. Cover with a second layer of sponge cake and repeat the last step for all layers.
6. Apply a layer of buttercream to the whole cake and smooth with a icing smoother.
7. Drizzle the melted chocolate glaze and drizzle it over the sides.
8. Decorate with swirls of the remaining buttercream and add Kinder Bueno.
9. Let it sit in the fridge for at least 2 hours and take it out 30 minutes before serving.