Cut butter into pieces. Knead butter, 60 g sugar, flour and 1 egg first with the dough hooks of the hand mixer, then with your hands to a smooth dough. Wrap dough in cling film and chill for about 30 minutes. Roll out the dough on a floured work surface and place it in a greased springform pan (26 cm Ø), pressing the edges together. Drain the mandarin oranges in a sieve. Wash lemon hot, grate dry and thinly grate half of the peel.
Squeeze 1/2 lemon. Separate 4 eggs. Bring cream and 150 ml milk to the boil. Mix 100 ml milk, pudding powder, lemon juice, egg yolks, salt, vanillin sugar and lemon zest. Stir the pudding powder into the cream and bring to the boil while stirring. In the meantime, beat 8 egg whites until stiff, adding 180 g sugar. Stir the quark into the pudding and bring to the boil again. Fold the beaten egg whites into the hot pudding. Finally fold in mandarin oranges. Pour the cheese mixture into the springform pan and bake in the preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: level 2) for 40-50 minutes. If the cake gets too dark, cover with aluminium foil.
In the meantime, beat 8 egg whites until stiff, adding 180 g sugar. Stir the quark into the pudding and bring to the boil again. Fold the beaten egg whites into the hot pudding. Finally fold in mandarin oranges. Pour the cheese mixture into the springform pan and bake in the preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: level 2) for 40-50 minutes. If the cake gets too dark, cover with aluminium foil. Switch off the oven and open the oven door a little. After about 20 minutes, remove the cake from the oven, remove from the edge and allow to cool