1 Slide rack with ribs into upper-middle position and place foil lined pan on lower oven rack, making sure that foil covers rack. 2  Bake/roast ribs until fork-tender, 2-3 hours for spareribs and 1 1/2 hours-2 hours for baby back ribs. Mix a dry rub of the sugar, paprika, pepper, garlic powder and 1 1/2 teaspoons salt in a small bowl. 2  Mix mustard and liquid smoke in another bowl. 3  Lay ribs directly on removed oven rack and lightly sprinkle with salt. 4  Brush both sides of slab with mustard mix and then sprinkle both sides with dry rub.