Preheat the oven to 350°F (180°C). Sift the cocoa powder with the flour in a bowl. Beat the eggs with the sugar in a stand mixer bowl or with a hand mixer until fluffy. Stop beating, add the sifted cocoa and flour, and mix with a spatula. Place a 9.5-inch (24 cm) ring on a baking sheet (or close the bottom with aluminum foil) and pour the mixture inside.

Bake for about 25 - 30 minutes. The sponge cake is similar to a Black Forest cake without baking powder. Beat the mixture long enough for the eggs to whiten, as they give volume to the mixture. It doesn't rise much, so be careful when cutting. You can, of course, use another recipe!

Boil the sugar and water for 2 minutes, and once cooled, add the brandy.

Cut the sponge cake horizontally once it has cooled and soak it with the syrup.

Add the butter, powdered sugar, cocoa, and 2 tablespoons of the total heavy cream to the mixer bowl and mix with the paddle attachment on low speed. Then gradually add all the heavy cream, the vanilla extract, increase the speed, and beat for 2 minutes until you get a nice and light frosting.

Finish with the whipped cream (prepared by beating all the ingredients together), spreading it over the chocolate filling, either with a spatula or by making designs with a piping bag. You can also decorate with chocolate shavings or sprinkles.