In a small bowl, mix the brown sugar, black pepper, kosher salt, and paprika, using a fork to break up any chunks until thoroughly combined.
Using your hands, smother the ribs with the rub on both sides, pressing it into the meat on all sides.
Place the ribs in the Crockpot with the meaty side facing the wall of the slow cooker so the meat cooks thoroughly. Set the slow cooker to LOW.
Pour the BBQ sauce over the ribs, dousing them on all sides. Make sure there is plenty of sauce between the meaty side and the wall of the Crockpot so the meat does not stick and burn.
Cover and cook on LOW for 7 hours. If possible, spoon the sauce back over the ribs a few times during cooking to keep the meat moist.
The ribs are done when they are browned around the edges and the meat falls off the bone when you insert a knife between the bones.
Optional: to caramelize the sauce, broil the ribs in the oven for about 5 minutes at 400-450°F or on the broiler setting. Serve with extra sauce.
