Preheat the oven to 200°C.

Mix flour, salt and margarine and crumble everything between your hands. Add curd and applesauce, mix to a smooth dough. Form the dough into a ball, press it flat and place it, wrapped in a transparent film, in the refrigerator.

Skin the potatoes and cook them for 25 minutes in boiling salted water. Cut the potatoes into pieces. Skin the apples and cut them into pieces. Skin the onions, cut them into rings and steam them with a little bit of margarine. Slice the mozzarella.

Line a pie plate with the dough and pierce it several times with a fork. Spread everything onto the dough. Cover the pie with the remaining dough.

Bake it in the preheated oven at 200°C for about 25 to 30 minutes.