Place sausage & water in non-stick (large) fry pan. Cover and cook 8 minutes over medium heat. Stir occasionally. Remove to warm plate. Pour off drippings.
Melt 1 Tablespoon butter in same fry pan, cook apples & onions 4 minutes till apples tender. Remove to warm plate with sausage.
Melt remaining butter in fry pan cook potatoes till tender, golden brown (covered). Stir occasionally. Mix vinegar & sugar. Reduce heat toss sausage, apples, onions, potatoes, caraway seeds (if using) and vinegar mix in pan. Sprinkle with parsley.