1. Cut the onion into wedges and place in a food processor. Add garlic, vinegar, cumin, red pepper flakes, oregano, salt and cayenne. Whirl the until onion is very finely chopped, stopping to scrape down sides as necessary.
2. Spread both sides of the ribs with onion mixture. Place ribs in a resealable plastic bag or flat dish. Close bag or cover dish and refrigerate for at least 6 hours or up to 1 day. Turn the ribs once during marinating time.
3. When ready to cook, oil grill and preheat barbecue. Set barbecue temperature to medium or medium - low. Barbecue with lid down or loosely covered with foil, turning once or
twice, until deep golden with slightly singed areas, about 50 to 60 minutes. If ribs are browning too quickly, move to a cooler part of grill or reduce heat.
For appetizers, serve individual ribs.
Tip - Removing the Pork Rib Membrane
Some people find that a screwdriver or oyster knife works well for this task. Use whatever tool works best for you. Once you get a small area pried up, grasp it with a paper towel and pull it off toward the other end of the slab, and if you do it correctly (it comes with practice), you should be able to remove the membrane with one movement.
