Knead the ingredients for the dough into a shortcrust pastry. Press this into a greased springform pan or tart pan and form an approx. 3 cm high rim. Sprinkle 1 tablespoon of cornstarch on the bottom. Put the mold with the batter in the refrigerator.
Bring 500 g currants to the boil in a saucepan for about 5 minutes and then strain them through a sieve. Collect the juice, that should add up to approx. 300 ml. With the pudding powder, the juice and 3 tablespoons of sugar, cook a thick red currant groats.
Then spread the 250 g currants and 250 g strawberries together with the grits on the floor.
Pre-bake in a preheated oven at 180 ° C for approx. 20 minutes.
In the meantime, prepare the crumble and spread it on the pre-baked cake.
Bake for another 30 minutes at 160 ° C. Allow to cool in the mold.
The cake is perfect when the filling is still slightly runny.