Cook onion in hot fat until tender but not brown. Add meat; brown lightly. Place noodles in layer over meat. Combine remaining ingredients except sour cream; pour over noodles to moisten all. Bring to boiling; cover, and simmer over low heat 30 minutes, or until noodles are tender. Stir in sour cream, heat just to boiling. Season to taste. Garnish with onion rings, if desired. Makes 6 servings. Submitted by Suzy Lewis