In large skillet, cook onion in hot oil until almost tender. Add meat and garlic; brown lightly. Add remaining ingredients. Simmer uncovered 2 to 2 1/2 hours or till sauce is thick; stir occasionally. Remove bay leaf. Serve over hot spaghetti. Garnish with Parmesan cheese, if desired. NOTE: One pound of spaghetti will serve 4 to 6 as a main dish with sauce.