Melt the butter and let it cool down. Chop the chocolate and melt over a warm water bath. Leave to cool a little. Mix the cooled butter, sugar and vanilla sugar with the whisk of the hand mixer until creamy. Separate 5 eggs.
Stir the egg yolks one after the other into the fat-sugar mixture. Stir in curd cheese, mascarpone, pudding and sauce powder. Halve the quark mixture. Stir the chocolate into one half. Beat egg whites and a pinch of salt until stiff. Halve the beaten egg whites and fold into 1 quark mixture each. Pour light and dark quark mixture alternately into a greased springform pan (26 cm Ø). Pull the mixture spirally with a fork. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 1 hour on the 2nd rack from below. Let the cake rest in the switched off oven for approx. 15 minutes.
Pour light and dark quark mixture alternately into a greased springform pan (26 cm Ø). Pull the mixture spirally with a fork. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for about 1 hour on the 2nd rack from below. Let the cake rest in the switched off oven for approx. 15 minutes. Remove from the oven and let it cool down. Remove the cake from the edge of the springform pan with a knife and take it out of the pan. Decorate with chocolate rolls and dust with icing sugar
waiting time approx. 2 hours