Mix together margarine, sugar and vanilla sugar, mix in eggs and 100 ml milk. Mix the flour and baking powder and mix with the rest of the batter. Spread on a greased baking sheet (26 x 39 cm). Bake in the preheated oven for approx. 15-20 minutes at 160 ° C.
Pour sour cherries through a sieve and allow to drain, but catch the juice. Mix this with approx. 30 g cornstarch until lump-free and let it boil briefly.
Make the custard with the milk according to the instructions.
Spread the cherry compote and warm pudding in strips (or any other desired pattern) on the cooled dough base.