Cook garlic in butter until lightly browned.
Add ketchup, brown sugar, Worcestershire, liquid smoke, salt and pepper and water; heat to boiling.
Reduce heat to low, cover and simmer 10 minutes, stirring occasionally.
Arrange chicken pieces (if using with skins, arrange skin-side up) in an open roasting pan.
Put onion slices over the chicken.
Pour sauce over chicken and onions.
Bake 1 hour 15 minutes at 375° F.
Serve over steamed rice.