For the yeast dough baking mix, enclosed dry yeast, 1 egg and 100 ml lukewarm water in a bowl and knead with the dough hooks of the hand mixer to a smooth dough. Cover and leave to rise in a warm place for about 30 minutes. In the meantime, mix flour and 75 g sugar for the crumbles. Melt 75 g fat and add. Knead into crumbles with your hands and set aside. Drain the mandarin oranges.
Sort and wash the gooseberries. Bring approx. 1/4 litre of water to the boil in a wide saucepan and stew the gooseberries covered in it for 5-7 minutes. Drain well on a sieve. Stir the remaining fat and 100 g sugar until creamy. Stir in remaining eggs. Add custard powder, lemon zest, quark, sour cream and cinnamon and mix. Knead the yeast dough again on the floured work surface and roll out on a greased baking tray. Prick several times with a fork. Spread fruit on top. Spread the quark and sour cream mixture over the fruit. Sprinkle with crumbles and bake in a preheated oven (electric: 200 °C/ gas: level 3) for approx. 40 minutes.
Add custard powder, lemon zest, quark, sour cream and cinnamon and mix. Knead the yeast dough again on the floured work surface and roll out on a greased baking tray. Prick several times with a fork. Spread fruit on top. Spread the quark and sour cream mixture over the fruit. Sprinkle with crumbles and bake in a preheated oven (electric: 200 °C/ gas: level 3) for approx. 40 minutes. Let it cool down and dust with icing sugar. Results in approx. 16 pieces