Knead flour, butter, cocoa and 90 g sugar first with the dough hooks of the hand mixer, then with your hands to a smooth dough. Spread the dough on the greased, mnit flour sprinkled fat pan of the oven (32 x 39 cm) and press it firmly. Put the base in a cool place. Cut lemon in half and squeeze. Peel 4 bananas and cut them into small pieces. Puree yoghurt, 1 tablespoon lemon juice, bananas and vanilla sugar.
Mix 300 g sugar, quark and yoghurt. Stir in the eggs first, then the pudding powder one after the other. Spread the quark mixture evenly on the chocolate base. Bake the cake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 60 minutes. Remove the cake from the oven and let it cool down on a cake rack. As soon as the cake is cold, cut 6 bananas in half lengthwise and sprinkle with the remaining lemon juice. Pat the bananas dry and spread 6 rows, 2 bananas each side by side on the cake. Put the cake glaze and 2 tablespoons of sugar in a pot. Stir in 250 ml cold water. Bring the glaze to the boil while stirring and spread it quickly from the middle over the bananas and cake. Put the cake in a cool place for about 45 minutes. Warm up the nut nougat cream and put it into a disposable piping bag or freezer bag.
Put the cake glaze and 2 tablespoons of sugar in a pot. Stir in 250 ml cold water. Bring the glaze to the boil while stirring and spread it quickly from the middle over the bananas and cake. Put the cake in a cool place for about 45 minutes. Warm up the nut nougat cream and put it into a disposable piping bag or freezer bag. Cut off a small corner and squirt strips over the cake. Whip the cream until stiff and fill into a piping bag with star-shaped spout. Cut the cake into 24 pieces and decorate with cream tuffs and colourful crumbles