Boil the potatoes until soft. Drain off all the water. Add the milk and heat thoroughly; season to taste. Work the butter into the flour and then add the egg and 1/4 cup milk, using only enough milk to make mixture thin enough to drop into the hot milk. Add to hot milk mixture. Cover the saucepan and cook about 10 minutes. Serve at once.
Dutch Cook Book - Fine Old Recipes, Culinary Arts Press, 1936.