Rinse spareribs under cold running water, and pat dry with paper towels. Sprinkle both sides of ribs with salt and pepper. Place in a large shallow roasting pan, and brush both sides of ribs with 1 cup sauce. Cover pan with aluminum foil. Bake at 350º for 1 1/2 hours. Turn ribs, and bake 1 1/2 more hours or until tender. Drain excess oil from pan.
Set aside 2 cups sauce for dipping. Brush each slab of ribs with the remaining sauce. Grill, covered with grill lid, over medium heat (300º to 350º) for 25 to 30 minutes. Turn often to avoid burning, and baste with sauce as needed. Serve ribs with reserved sauce.