Line a springform pan (26 cm Ø) at the bottom with baking paper. Separate the eggs. Beat the egg whites and 5 tbsp. water until stiff, adding 150 g sugar and vanillin sugar. Beat the egg yolks separately into the mixture. Sift flour, starch, baking powder and cocoa into the mixture and fold in. Brush into the mould. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/gas: level 2) for approx. 30 minutes. Cooling down
Mix the pudding powder, 3 tablespoons of sugar and 6 tablespoons of milk. Boil up the rest of the milk. Stir in the pudding powder, bring to the boil briefly. Let it cool down
Finely grind the walnuts, up to approx. 26 halves, in the universal chopper. Cream butter and 50 g sugar. First stir in the pudding by the spoonful, then all ground nuts
Cut the biscuit 2 x horizontally. Spread 1/2 cream on the 1st base, place 2nd base on top. Spread the rest of the cream on it, place the 3rd base on top. Chill for about 2 hours.
Chop the entire chocolate coating and melt in a hot water bath. Spread the cake with it. Chill for about 30 minutes.
If necessary, press cake dividers for approx. 18 cake pieces into the couverture. Decorate with the rest of the nuts. Cool for about 1 hour