Grind the chocolate and melt it with butter in a water bath.
Stir until smooth.
Beat eggs with sugar.
In the cooled chocolate mass add beaten eggs, cocoa flour and baking powder.
Mix well to a homogeneous dough without streaks. Grease the baking dish with butter and sprinkle with semolina (if necessary). Put the chocolate dough, level.
Peel the banana, cut into pieces and use a blender to chop.
Mix banana with cottage cheese, sour cream and sugar. If the cheese watery, you can add a spoon of semolina.
Spread the banana layer on top of chocolate.
Circular motion of a fork to slightly mix the layers to make beautiful stains.
Bake the brownies in a preheated 180 degree oven for about 30-35 minutes.
Or in a slow cooker on the "Baking" for about an hour (may have to add 5-10 minutes).