Pat ribs dry using paper toweling, and season with salt and pepper. Place ribs in a 13 x 9 baking dish lightly sprayed with cooking spray. Cover with aluminum foil and bake for 1 ½ hours, or until pork is no longer pink inside.
While ribs are cooking in a large saucepan using the oil over medium-high heat cook the onion and garlic until the onion starts to brown. Mix the rest of the ingredients into the onion mixture, bring to a boil, and reduce heat to a high simmer. Stir and cook until mixture thickens significantly; about 15 minutes.
Prepare grill. Grill ribs covered over indirect heat brushed with the sauce. Brush and turn ribs frequently. Grill until ribs are tender and slightly charred.