A favorite of my mother’s. An easy way to test your dough is to form a small dumpling and test cook it. The result should hold together and be al dente without being too rubbery.
Wash, peel and cut up potatoes. Cook about 20 minutes in enough salted water to cover the potatoes. Potatoes are done when they can be pierced with a fork. Drain.
Mash or rice potatoes well. Whip in the egg yolk and 1 ½ tsp salt. Set aside while you prepare filling.
Put onions in a cold skillet and fry with a little oil or butter until soft. Remove from pan. Add meat to pan and cook until crisp and evenly browned. Add back in onions. Drain off excess fat.
To make dough: Add the flour 1 cup at a time and mix well. Add as much of the flour to make a soft dough. Once dough has formed, form each dumpling by hand into approximately 3 inch rounds. Spoon about 2 teaspoons of the filling into the center of each round. Seal edges well, and shape into a ball.
Bring the 2 quarts of water and 2 tsps salt to a boil in a heavy saucepan. Once the water is boiling add dumplings one at a time, so that boiling does not stop. Cook only as many dumplings at one time that will float uncrowded, one layer deep. Cook each dumpling until it floats to the top of the water, then remove with a slotted spoon. Put in a warm dish and serve with melted butter and jam.