Rinse each slab under cool water. Ensure the membrane under the ribs has been removed. If there is excess fat on your ribs, trim it off.
Add 2 Tablespoons of brown sugar, 1 Tablespoon smoked paprika, 1 Tablespoon chili powder, ¾ teaspoon garlic powder, ½ teaspoon freshly ground black pepper, 1 teaspoon salt, 1 teaspoon dry mustard to a medium-sized bowl and mix well.
Massage on both the front and back of the ribs.
After the smoker is prepared and pre-heated, place each slab on the smoker racks, bone side down. Lather on the BBQ sauce and smoke low and slow on 225°F.
After 2 hours, open the smoker and remove the ribs with a pair of tongs. Place them on a long piece of heavy-duty aluminum foil.
Using a basting brush, add another layer of BBQ sauce. Wrap each slab individually and tightly in the foil. The tighter the better.
Place the aluminum wrapped slabs of ribs back in the smoker, bone side up, and smoke for another 2 hours.
Remove the aluminum foil packet and unwrap. Add another layer of BBQ sauce and place them back on the smoker, bone side down, for 1 more hour.
After they are done smoking, remove each rack from the smoker and place them on a long cookie sheet. Let them rest for 5-10 minutes before serving.