Let's start by preparing the filling.
In the bowl of a food processor, add: cottage cheese, sugar, vanilla sugar, egg and cornstarch, mix until you get a smooth texture.
For the dough: in a bowl, mix the sifted flour, cocoa powder, salt and baking powder.
In another bowl, mix the eggs with the sugar and vanilla sugar for 7-8 minutes.
Pour in the milk and melted butter, add the dry mixture, and fold the ingredients together until there are no lumps left.
Transfer the mixture to a baking sheet lined with baking paper, add the cheese filling in places. Spread the filling with a toothpick.
At your request, add berries or fruits.
Bake in the preheated oven at 170 °C for 30-35 minutes.
Take it out, let it cool for 5 minutes, cut it and serve it with pleasure.