For the dough: 2.3 cups of self-rising flour, 100 g of margarine, 1 jar of sour cream (170 ml)
For the filling: 3 tablespoons butter, 6 large onions, finely chopped, 250 g fresh or canned mushrooms (strained and chopped), 1/2 cup cream (125 ml), 1 teaspoon mushroom soup powder, salt and black pepper to taste, 3 beaten eggs, 200 g grated cheese

Place flour, margarine and sour cream in a bowl. Knead the dough and cool it in the refrigerator for about 30 minutes. Lubricate the baking sheet and lay out the bottom with dough. Heat oven to medium temperature. Prepare the filling: melt the butter in a frying pan and fry the onion in it until golden brown. Add mushrooms and fry for another 5 minutes, stirring all the time. Add cream, soup powder, season with salt, pepper and cook for 4 minutes until the mixture thickens. Transfer to a bowl, cool slightly. Add eggs, mix and spread the mixture on the dough in a baking sheet. Bake in preheated oven for 15 minutes or until browned. Sprinkle the casserole with a layer of grated cheese and bake for another 35 minutes over medium heat. Refrigerate for 15 minutes before serving.