Mix together the flour, sugar, fat, egg and baking powder and place in a cake tin.
For covering:
Drain the sour cherries and place on the dough.
Separate the eggs. Beat the egg yolks until foamy and mix with the fat, hazelnuts, sugar, flour and baking powder. Beat the egg white until stiff and fold in.
Then pour this mixture over the cherries and bake for about 70 minutes at 175 ° C.