1 c rye flour
1 c wheat flour
50 g butter
3/4 c water
salt
yolk to brush
Filling:
600 g fish fillet
2 ea onions
2 tb oil
2 tb milk

Knead dough, roll out finely 1 cm thick, sprinkle with flour and put in a fridge for a half an hour. Put the filling evenly on a half and cover with another one, pinch the edges and brush with yolk. Bake in a preheated oven on low heat for 1-1,5 hour. For the filling, grind fillet and onion in a mincer, add milk and oil and knead the filling.
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