Line the bottom of a springform pan (26 cm Ø) with baking paper. Separate 2 eggs. Beat 2 egg whites, 3 tbsp. cold water and 1 pinch of salt until stiff, adding 75 g sugar. Beat 2 egg yolks separately into the mixture. Sift flour, starch, cocoa and baking powder into the mixture and fold in. Brush into the mould. Bake in the preheated oven (electric cooker: 175 °C/circulating air: 150 °C/gas: level 2) for about 20 minutes. Cooling down
Break the dark and milk chocolate into pieces and melt in a hot water bath. Cool down a little. Whip 200 g cream until stiff. Separate 2 eggs. Beat 4 egg yolks and 2 tbsp. sugar until creamy. Stir in the liquid chocolate bit by bit. Beat 2 egg whites and 1 pinch of salt until stiff. Fold cream first, then beaten egg whites into the cream. Chill for about 30 minutes.
Soak the gelatine in cold water. Coarsely chop white couverture, melt. Whip 200 g cream until stiff. Separate 2 eggs. Beat 2 egg yolks, 1 tbsp. sugar and vanillin sugar until creamy. Squeeze out the gelatine, dissolve at low heat, stir into the warm chocolate coating. Stir immediately into the egg cream. Beat 2 egg whites and 1 pinch of salt until stiff. Fold cream first, then beaten egg whites into the cream. Chill for 5-10 minutes
Close the cake ring around the sponge cake. Spread the white and dark mousse alternately in 2 layers. Pull through spirally with a fork. Cool for at least 6 hours
Immerse the fir tree cookie cutter in hot water. Cut out chocolate bars with it. decorate the cake with little trees, chocolate rolls and strips