On a large cookie sheet, lay the ribs flat side by side. Clean the membrane off the back of the ribs. Remove any large chunks of fat.
Coat the back sides of the ribs with apple juice (orange juice or olive oil will work if you don't have apple juice). Lightly sprinkle the dry rub. Rub in as needed.
Flip the ribs over and coat the tops with apple juice. Sprinkle the remaining rub on the tops of both ribs. Rub into the meat and make sure the entire surface and sides are covered.
Let ribs sit for at least 20 minutes or as long as 12 hours. Refrigerate if left to sit longer than 20 minutes.
Prepare a crockpot with a cooking bag if desired. Set the crockpot to low.
Lightly coat the tops of the ribs with one bottle of Kansas City style sauce. You may need to cut the ribs in half to fit them into your crockpot.
Place each slab in the crockpot, top side down. This will help the meat to become more flavorful and juicy. Cook on low for six hours. Check periodically after four hours for tenderness. We don't want to overcook the ribs and turn them to mush. The meat is done when you can use a fork to pull the meat apart.
When the ribs are done cooking. Place them on a cookie sheet covered with aluminum foil. Make sure they are top-side up. Baste with additional sauce -- don't use the whole bottle, you will want to save some for dipping later.
Broil ribs for 3-5 minutes. You are trying to get the sauce to brown a little at the edges and make a nice caramelized crust on the top of the ribs.
Let ribs sit for 10 minutes. Cut and serve with additional sauce.