For the kneading dough mix flour with cocoa, baking powder, sugar and vanilla sugar. Add eggs and margarine and knead into a smooth dough. Refrigerate.
Knead the dough briefly again. Lay out 2/3 of the dough on a greased baking sheet.
For the filling, melt the butter and let it cool. Put the quark with sugar, pudding powder and eggs in a mixing bowl. Mix the ingredients into a smooth mass. Finally add the melted butter and stir in carefully. Now put the quark mixture on the dough base and smooth it out.
Distribute the drained mandarins evenly on the curd mixture. Pluck the remaining chocolate dough into pieces and distribute it decoratively on the cake.
Bake in a preheated oven at 160 ° C for approx. 40-45 minutes (test with chopsticks).