To roast garlic: Heat oven to 450 degrees. Remove outer layer of garlic bulbs skin. Slice about 1/4 inch or so off top of garlic to expose individual bulbs. Rub entire bulb with olive oil, wrap in foil and bake in oven for 30 minutes. Let cool enough to handle, then squeeze the garlic bulbs from the peel into food processor.
Cut tomatoes in half. Char halves under broiler or on a grill until all sides are nearly blackened. Add to food processor.
Add remaining ingredients to food processor and puree until smooth.
Coat the ribs on both sides with half the sauce. Let ribs marinate in the refrigerator for at least 15 minutes up to 8 hours. Reserve the remaining sauce to baste the ribs when grilling.
My preferred way to cook ribs is to place them in a roasting pan (add just a little bit of water to keep them moist while cooking and not stick to bottom of pan) and seal tightly with foil. Bake in a low oven, 250 degrees, for at least 3 hours. I typically don’t time them, just put them in early in the afternoon and let them do their thing. Then when it’s time to eat, take them out and finish them on the grill. Slather the extra sauce on ribs before putting them on the grill, then grill both sides to get them charred a bit and look like ribs are suppose to look. Baste with sauce while grilling as well. Since the ribs are already cooked, you really just trying to get the sauce to caramelize a bit and give some good color and BBQ flavor to the ribs.
*to measure 1/4 cup, just place the entire can of chipotles in adobo in your blender and blend to a puree. Then measure 1/4 cup. Don’t throw out the remaining sauce. Freeze it in tablespoon size portions for future recipes.