Dough for Pierogi or Uszka

On a pastry board mix flour, egg and salt, slowly adding water and kneading. The dough is ready if it does not stick to the hand or pastry board. Divide dough into four parts, and roll each one out thinly. With a wine glass cut out circles that are 2 - 21/2 in. in diameter. (For Uszka, cut out small squares). Place a teaspoon of the filling on each circle, fold over and press the edges firmly. Cook for 5 minutes. Sauerkraut and Mushroom Pierogi Filling Kapusta z Grzybami - nadzienie 2 cups sauerkraut 1 cup mushrooms 1 onion chopped butter salt pepper Cook sauerkraut for 10 minutes. Drain and chop well. Fry onion and chopped mushrooms in butter, add sauerkraut and fry until flavors are blended. Cool and fill dough circles. Potato Filling (Ruskie Pierogi) 1 lb cooked potatoes 6 oz cottage cheese 1 small egg 1 medium onion, finely chopped and sauted to golden salt pepper Run potatoes and cottage cheese through a meat grinder. Add egg to this along with onion. Add salt and pepper. Cheese Filling (Pierogi z Serem) 1 lb well drained cottage cheese 1 small egg salt Rub cottage cheese through a wire sieve, then mix thoroughly with 1 egg and salt. The filling swells during cooking, so do not use too much. Serve immediately, after pouring butter over them.