Bring the cream to the boil and remove from the heat. Break the chocolate into pieces and melt in it while stirring. Let it cool down and put it in a cool place overnight
Grease the springform pan (approx. 26 cm Ø). Chop the chocolate coating finely, dice 250 g butter. Melt both in 150 ml water with coffee powder at low to medium heat while stirring. Let cool down lukewarm for about 15 minutes
Mix flour, baking powder, sugar, vanillin sugar, salt and cocoa. Mix eggs and crème fraîche briefly. Alternately stir the couverture and egg mixture briefly into the flour mixture. Stir only until everything is mixed. Pour into the mould. Bake in the preheated oven (electric cooker: 175 °C/circulating air: 150 °C/gas: level 2) for approx. 1 hour. Cooling down
Cut the cake base in half once. Stir 400 g butter and icing sugar for about 3 minutes until creamy. Quickly stir in the cold chocolate cream by the spoonful. Stop when everything is stirred in. Put 2/3 cream for decoration in a cool place for about 10 minutes. Spread 1. half of the remaining cream on 1. base. Place 2nd base on top. Spread the 2nd half of the cream on the cake
Pour the rest of the cream into a piping bag (large perforated spout) and squirt dabs onto the cake. Chill for at least 2 hours. Dust thickly with cocoa before serving