Preheat the oven to 180 ° C. Line the bottom of two cake pans (18 cm and 14 cm in diameter) with parchment paper. Beat the eggs and sugar at maximum speed for 10 minutes. Sift the cacao and flour on top of the egg mixture and fold in with a spatula. Pour 2⁄3 of the batter into the large cake pan; add a teaspoon of cocoa powder to the rest of the batter and pour it into the smaller cake pan. Bake for 12 minutes. Take both sponges out of the cake pans and allow to cool on the cooling rack.
While baking the sponge, prepare the mixture for moistening the cake. Heat up the milk and sugar, then add the cream liqueur. Allow to cool.
While the sponge is cooling, prepare the filling. Bring 300 ml milk to a boil; mix the rest of the milk with egg yolks, sugar, pudding mix and vanilla paste until smooth. Stirring constantly, add the yolk mixture to the boiling milk and cook until thick. Cover the filling with plastic wrap in direct conta- ct and cool for about 10 minutes. Soak gelatin sheets in cold water for at least 5 minutes. Whip the cream and refrigerate. Dissolve the wrung-out sheets of gelatin in the warm filling and mix until smooth with a mixer. Di- vide the filling into two parts; melt the milk chocolate in one part and the white chocolate in the other. Cover both fillings with plastic wrap in direct contact and cool until lukewarm.
Place the larger sponge on a stand, moisten it and fit the cake ring. Mix the chocolate filling until smooth, add chopped up chocolate chip cooki- es and finally fold in 130 g of whipped cream with a spatula. Evenly spread the filling on top of the sponge and refrigerate. Stir the white chocolate filling until smooth and fold in the remaining 130 g of whipped cream with a spatula. Place the chocolate sponge on top of the milk chocolate filling and moisten. Coat with the white chocolate filling (fill the space around the sponge first) and level out the surface. Refrigerate to chill and set the cake.
Bring cream to a boil and pour over the chocolate. Wait one minute, mix until smooth and add the cream liqueur. After the glaze has cooled a bit, pour it over the filling. Chill the cake for at least 5 hours.
Remove the cake ring from the chilled cake and decorate as desired.