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 Dutch oven, bring water and bouillon to a boil. , Meanwhile, combine first four knoephla ingredients to form a stiff dough. Roll into a 1/2-in. rope. Cut into 1/4-in. pieces and drop into boiling broth. Reduce heat; cover and simmer for 10 minutes. Add the potato mixture; heat through. Sprinkle with parsley if desired.