In a large skillet, melt butter; cook potatoes and onion for 20–25 minutes or until tender. Add milk; heat through but do not boil. Set aside. In a soup kettle or Dutch oven, bring water and bouillon to a boil. Meanwhile, combine knoephla ingredients to form stiff dough. Roll into a 1/2-inch rope. Cut into 1/4-inch pieces and drop into boiling broth. Reduce heat; cover and simmer for 10 minutes. Add the potato mixture; heat through. Yields 8–10 servings or 2-1/2 quarts.