Drain the cherries and collect the juice. Cream butter and 250 g sugar. Stir in the eggs one by one. Mix flour, baking powder and cocoa and stir in briefly. Spread the dough evenly on a greased baking tray (38 x 32 cm). Spread cherries on top.
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for 30-35 minutes. Let them cool down. In the meantime, soak gelatine in cold water for the cream. Mix quark, 50 g sugar, lemon juice, butter-vanilla flavouring and sour cream. Squeeze out the gelatine, dissolve lukewarm. Stir 2 tablespoons of the cream into the gelatine. Stir the gelatine into the rest of the cream. Spread evenly on the base, refrigerate for about 30 minutes. For the top layer, mix Red Groats Powder and 75 g sugar. Gradually stir with 8 tablespoons of cold water until smooth. Bring 1/2 litre of collected cherry juice to the boil. Stir in the mixed powder, bring to the boil again.
Spread evenly on the base, refrigerate for about 30 minutes. For the top layer, mix Red Groats Powder and 75 g sugar. Gradually stir with 8 tablespoons of cold water until smooth. Bring 1/2 litre of collected cherry juice to the boil. Stir in the mixed powder, bring to the boil again. Let it cool down a little and spread it carefully on the cream. Allow to set completely and cut into wavy pieces. Decorate with a tender strip of stiffly whipped cream