To prepare barbecue sauce, sauté onion in butter until soft, about 3 to 5 minutes. Add remaining ingredients and bring to a boil. Reduce heat and simmer for about 30 minutes.
To prepare ribs, combine beer and liquid smoke. Pour over meat and let stand 10 to 30 minutes.
Drain meat and place 2 cups marinade in the bottom of a roasting pan. Place meat on a rack in roasting pan. Place onion slices and garlic cloves on top of meat. Cover pan with foil and bake at 300° F for 1 1/2 to 2 hours or until tender. When cool enough to handle, rub ribs with meat rub. Serve with barbecue sauce.
Makes: 4