Remove the membrane from the back of the ribs. Use a butter knife or your fingers to loosen and lift a corner of the membrane. Grip it with a paper towel to pull it off.
In a large stockpot, sauté onion and garlic with until tender. Add the ribs, crushed coriander seeds and enough chicken broth to cover the ribs.
Bring to a boil, reduce and simmer on low, covered for about 2 hours, until ribs are fully tender.
GRILL - Preheat the bbq to medium heat. Remove the ribs from the boiling water and discard water and onions. Using a brush, baste ribs with bbq sauce and put on grill, meatier side down. Grill for about 10 minutes, continually turning and basting with bbq sauce as needed.
BROIL - Carefully transfer ribs to a baking sheet lined with aluminum foil. Brush generously with barbecue sauce. Place under the broiler for 3-4 minutes, or until the sauce caramelizes and becomes slightly charred.
Serve immediately with extra BBQ sauce on the side.