Line the bottom of a springform pan (26 cm Ø) with baking paper. Separate the eggs. Beat the egg whites, 4 tbsp. cold water and 1 pinch of salt until stiff, while pouring in sugar and vanilla sugar. Fold in the egg yolks one at a time.
Sift the flour, pudding powder and baking powder on top and fold in.
Spread the sponge cake into the mould. Bake in the preheated oven (electric cooker: 175°C/circulating air: 150°C/gas: level 2) for approx. 25 minutes. Let them cool down.
Coarsely chop the couverture and nougat. Bring the cream to the boil, remove from the stove. Melt the nougat and 150 g chocolate coating while stirring. Cool down. Then chill for at least 5 hours.
Cut the biscuit 1x so that the top is thin and the bottom is thick. Whip nougat cream in 2 portions until stiff. 2⁄3 Spread it dome-shaped on the thick base and place the thin one on top.
Spread the cake with the remaining nougat cream. Chill for about 4 hours.
Melt 50 g chocolate coating and 1 teaspoon butter in a hot water bath. Spread on the middle of the cake to form a circle (10-12 cm Ø) and chill for approx. 15 minutes. Decorate with "Toffifees".