Ingredients
- 2 1/2 tablespoons kosher salt
- 1 tablespoon dry mustard
- 1 tablespoon paprika
- 1/2 teaspoon cayenne pepper
- 1/2 teaspoon freshly ground black pepper
- 8 pounds St. Louis-style spareribs (4 racks)
- 1 1/2 cups store-bought or homemade barbecue sauce plus more
Preparation
Step 1
Preheat oven to 350°F. Combine first 5 ingredients in a small bowl. Place each rack of ribs on a double layer of foil; sprinkle rub all over ribs. Wrap racks individually and divide between 2 baking sheets.
Bake ribs until very tender but not falling apart, about 2 hours for baby backs and 3 hours for spareribs. Carefully unwrap ribs; pour any juices into a 4-cup heatproof measuring cup; reserve juices. Let ribs cool completely. Cover and chill juices. Re-wrap ribs in foil and chill. DO AHEAD: Ribs can be baked up to 3 days ahead (the flavor will be more developed, and easier to grill as when cold).
Heat a gas grill to high. Add water to rib juices, to measure 1 1/2 cups. Whisk in barbecue sauce to blend (or use straight barbecue sauce).
Grill ribs, basting with barbecue sauce and turning frequently, until lacquered and charred in places, 7-10 minutes.