Mix the rub ingredients together in a small bowl and rub it all over the racks of ribs. If you prep them in advance, wrap them in plastic wrap and refrigerate until you are ready to cook them.

Place the ribs, meat side out (facing the slow cooker wall). into the slow cooker, standing up. They should curve along the wall of the slow cooker. Longer rib racks should be stacked against the racks that are sitting against the pot walls.

Pour the barbecue sauce over the ribs.

Cover the slow cooker and cook on low for six to eight hours.

Once the ribs are done, remove them from the slow cooker and let them sit, tented with foil, while you prepare the basting sauce.

Remove the slow cooker insert to let it cool for about five minutes and then skim the fat from the top of barbecue sauce and juices. Pour the sauce into a sauce pan and simmer to reduce it for about 20 minutes, until you have two cups of sauce.

Line a half sheet pan with foil and top with a cooling rack that has been sprayed with a nonstick spray oil.

Place an oven rack about 10 inches below the broiler and preheat the oven to broil.

Place the rib racks, bone side up, on the sheet pan and wire rack, and brush liberally with the reduced barbecue sauce.

Broil the ribs for about 4 minutes.

Turn the ribs over, brush with barbecue sauce, and broil for another 10 minutes, brushing again liberally with sauce about half way through.

Move the finished ribs to a cutting board and tent them with foil for about 10 minutes. Cut the ribs individually and serve with the basting sauce.