Finely chop meat and onions, mix well, and add salt and spices. Make stiff dough out of flour, egg, salt, and water, let stand for 10 minutes. Roll out dough into flat layer about 1-2 mm and cut into 10x10 cm squares. Place a tablespoon of filling and a piece of chopped fat in the center of each square, pinch edges up around the filling forming rectangular or triangular dumplings. Place manti on greased layer of steamer, and steam 45 minutes. Serve in plates, putting 4 manti on each, top sour cream and sprinkle with ground black pepper.