Put fatty meat through meat-grinder, add, salt, black pepper, 1-2 chopped onions and mix well. Put the bones from the meat into a pot with water to start the broth. Add rest of onions, tomatoes, salt and spices to taste. For the dumplings, make a fairly stiff dough and let stand for 30-40 minutes. Roll into thin layer and cut into 4x4 sm squares. Put a teaspoon of meat filling in the center of each square and pinch the ends together to completely close. Add water if necessary and bring to a boil. Put in dumplings and cook until they rise to the surface. then simmer another 3-4 minutes. Serve dumplings with broth in kosas, garnished with greens and freshly ground black pepper.