Combine brown sugar, paprika, cayenne pepper, salt and black pepper in a bowl.

Rub ribs with the sugar/spice mixture and place them in the crock-pot. Stand them up along the inside of the crock-pot with the meaty side facing the walls.

Pour the barbecue sauce over the ribs and use a brush to make sure they are covered.

Cook ribs in crock-pot on low for 6 hours.

Cover a cookie sheet with foil and place a wire rack over it. Spray the rack with cooking spray.

Place cooked ribs on the wire rack. Pour sauce into a saucepan.

Cook the sauce over medium-high heat about 10 minutes. Turn oven to high broil.

Brush the heated sauce over cooked ribs and place them in the oven and broil for 2-3 minutes or until sauce looks caramelized.