Grease the bottom of the springform pan (26 cm Ø) and dust with flour. Chop 50 g dark chocolate coating, melt with 30 g butter in a water bath. Cooling
Separate eggs. Beat the egg whites, 3 tablespoons of cold water and 1 pinch of salt until stiff, adding sugar and 1 vanillin sugar. Beat the egg yolks separately. Briefly fold in the melted chocolate coating. Mix 50 g flour, starch, cocoa and baking powder, sieve onto the egg 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 approx. 30 minutes. Cooling down
Soak the gelatine in cold water. Squeeze out, dissolve at low heat. Stir in liqueur by the spoonful. Chill for approx. 25 minutes until it begins to gel. Whip 400 g cream and 2 vanillin sugars until stiff. Fold into the liqueur
Cut the sponge in half horizontally. Spread 2/3 liqueur cream on the bottom cake layer. Place 2nd base on top. Spread the rest of the liqueur cream on the edge of the cake. Chill for at least 5 hours, preferably overnight
Heat 150 g cream (do not boil!). Chop 150 g dark chocolate coating. Melt in it with plate-grease while stirring. Cool down for 30 minutes. Chill for 30 minutes until it is viscous
Chop white couverture, melt in hot water bath. Spread dark chocolate icing on the cake. Pour white chocolate coating into the plastic bag, cut off a small corner. Spray the chocolate coating in strips on the cake and pull it through from the side with a wooden stick, alternating to the right and left. Chill for about 2 hours