For the banana cake, first prepare the dough. Mix the butter with the sugar and vanilla sugar until creamy, gradually adding the eggs. Mix flour with baking powder and sift over the mixture.
Fold in with the milk. Grease and flour a baking pan and pour in the mixture. Bake in a preheated oven at 170 °C for about 40-45 minutes. When the cake has cooled, cut through once. For the cream, whip the cream until stiff and mix well with the powdered sugar, vanilla sugar and curd. Place the base in the springform pan, cut the bananas in half and cover the base with them.
Spread the curd mixture on top and cover with the second cake layer. Chill in the refrigerator for a few hours. For the chocolate cream, cream the butter, melt the chocolate in a bain-marie and mix with the powdered sugar and butter.
Coat the cake all around and on top with the cream. Cut the fruit into pieces and decorate the cake with them.