Using a sharp knife, slice rack of ribs in half so you have two small racks. Generously sprinkle and rub the Stubb's Pork Rub all over ribs. If you don't use the dry rub (which I recommend because it's delicious!), rub your ribs down with a tsp of salt and pepper.
Place both racks at the bottom of your Crock Pot.
Place diced onions on top of ribs in the pot, followed by minced garlic. Finally, pour barbecue sauce over everything.
Place lid on Crock Pot and turn heat to low. Cook for 7 hours---meat should be definitely falling off the bone at this point!