Step 1Heat the oil in a medium saucepan over medium heat. Add the minced onion and jalapenos and saute, stirring, until soft and starting to brown, about 10 minutes. Stir in the bourbon (or rum) and cook 2 minutes to reduce slightly. Add the ketchup, vinegar, mustard and Worcestershire sauce and mix well, then add the maple syrup. Simmer, stirring often, for 30 minutes, until the flavors have blended. Season with salt and pepper to taste.
Step 2While the sauce is simmering, put water in a large steamer or a roasting pan with a rack. Add the thyme sprigs, bay leaves and sliced onion and bring to a simmer. Lay the ribs on the rack over the simmering water. Cover and steam 30 minutes. Transfer to a shallow dish and pour the hot sauce over. Let stand 15 minutes.
Step 3Heat the grill until smoking. Brush excess sauce off the ribs. Grill, basting lightly with sauce, until done, turning often to keep from charring too much, about 10 to 15 minutes. Serve the remaining sauce on the side.