Cook mushrooms in butter in 10 inch skillet until limp. Remove from skillet. Sprinkle beef strips with paprika. Brown well in skillet. Stir in mushrooms, soup mix, and water. Heat to boiling. Lower heat. Cover. Simmer 30 minutes or until meat is tender.

Just before serving, combine imitation sour cream and flour. Stir into meat mixture. Heat until steaming. Serve immediately over hot buttered noodles. Makes 8 servings, 2/3 cup each.