Separate eggs, beat egg whites and 2 tablespoons of water until stiff. Add sugar and 1 sachet of vanilla sugar. Stir in egg yolk. Mix flour, cornstarch, cocoa and baking powder, sieve onto the egg mixture and fold in carefully. Line the bottom of a springform pan (20 cm Ø) with baking paper.
Fill in the dough and smooth it down. Bake in the preheated oven (electric: 175°/ gas: level 2) for 15-20 minutes. Remove the cake base from the oven, remove from the springform pan, let it cool down and cut through horizontally once. Cut the chocolate cake into small rolls with a peeler. Clean and wash the Cape Gooseberries and cut some in half. Spread the lemon jelly on the bottom layer. Whip the cream until stiff, pour in the remaining vanilla sugar and fold in the lemon peel. Spread half of the lemon cream on the lower cake layer, place the second layer on top and spread the cake with the remaining lemon cream. Serve the coated cake decorated with chocolate rolls and Cape Gooseberries.
Spread the lemon jelly on the bottom layer. Whip the cream until stiff, pour in the remaining vanilla sugar and fold in the lemon peel. Spread half of the lemon cream on the lower cake layer, place the second layer on top and spread the cake with the remaining lemon cream. Serve the coated cake decorated with chocolate rolls and Cape Gooseberries. Decorate as desired with lemon balm. Makes about 12 pieces