Separate eggs, beat egg whites and 4 tablespoons of water until stiff. Finally, add sugar, except for one teaspoon, and vanilla sugar. Stir in the egg yolks one after the other. Mix flour, cornstarch and baking powder, sieve onto the egg foam and fold in loosely. Spread on a baking tray (approx. 39x32 cm) lined with baking paper. Bake in a preheated oven (electric: 200 °C/ gas: level 3) for 10-12 minutes.
Immediately turn onto a clean, damp tea towel and remove the baking paper. Wrap the sponge cake in the cloth and let it cool down. In the meantime, heat 100 ml milk and dissolve the espresso powder in it. Let it cool down. Chop the chocolate. Put the cream cake powder in a high mixing bowl. Add the rest of the milk and cold espresso milk and stir with the whisk of the hand mixer first at the lowest setting, then at the highest setting for about 2 minutes until creamy. Cream softened butter with the whisk of the hand mixer. Add cream and chopped chocolate at once and stir to a smooth cream. Spread on the sponge cake and roll up from the long side. Put the roll in a cool place for about 2 hours.
Add the rest of the milk and cold espresso milk and stir with the whisk of the hand mixer first at the lowest setting, then at the highest setting for about 2 minutes until creamy. Cream softened butter with the whisk of the hand mixer. Add cream and chopped chocolate at once and stir to a smooth cream. Spread on the sponge cake and roll up from the long side. Put the roll in a cool place for about 2 hours. In the meantime, roughly chop the chocolate coating and melt it in a water bath. Put the couverture in a small freezer bag, cut off a small corner and decorate the roll with chocolate strips. Refrigerate again briefly. Whip the cream and the remaining sugar until stiff and place in a piping bag with a star-shaped spout. Cut the sponge cake into 11-12 cake pieces and decorate each with a cream tuff, mocha beans or candied cherries. Results in 11-12 pieces
In the meantime, roughly chop the chocolate coating and melt it in a water bath. Put the couverture in a small freezer bag, cut off a small corner and decorate the roll with chocolate strips. Refrigerate again briefly. Whip the cream and the remaining sugar until stiff and place in a piping bag with a star-shaped spout. Cut the sponge cake into 11-12 cake pieces and decorate each with a cream tuff, mocha beans or candied cherries. Results in 11-12 pieces
(at 12 pieces)