For the crumbled dough, mix 625 g flour, 270 g sugar, cocoa, 1 packet of vanilla sugar and 1 pinch of salt. Add 450 g butter in pieces and knead everything into crumbles using the dough hooks of the mixer. Approx. 2⁄3 Spread the crumbles in a greased fat pan (32 x 39 cm) and press them to a base. Cover the rest of the crumbles and put them in a cool place. Wash the cherries, remove the stalks and pit them.
Separate the eggs for the cheese mixture. Beat the egg whites with 1 pinch of salt until stiff in portions. Mix 100 g butter with 300 g sugar. Add quark, sour cream, egg yolk, pudding powder and 1 sachet of vanilla sugar and stir in. Fold in the beaten egg white in portions. Spread about half of the cheese mixture on the pastry base and smooth it down. Spread the cherries on top. Pour the rest of the cheese mixture over it.
Dust the remaining crumbles with 1 tablespoon of flour. Spread them on the cheese mixture, rubbing lightly between your fingers. Bake in the preheated oven (electric cooker: 180 °C/circulating air: 160 °C/gas: see manufacturer) for about 1 hour. Let it cool down. Dust with icing sugar.