Ketchup, vinegar, and spicy brown mustard sweetened with a touch of brown sugar create a succulent sauce for this grilled pork baby back rib main-dish recipe.
Heat oven to 400°. Place ribs in a 13 x 9 x 2-inch baking dish and cover tightly with foil. Bake at 400° for 1 hour. Drain off any accumulated liquid.
Meanwhile, in a medium-size saucepan, stir together the ketchup, vinegar, mustard, brown sugar, 3 tablespoons water, the onion powder and hot sauce. Cook over medium-low heat for 10 minutes, stirring. Place half the sauce in a small bowl; set aside.
Heat gas grill to medium-high or prepare charcoal grill with medium-hot coals. Lightly coat grill rack with oil or nonstick cooking spray.
Baste ribs generously with the remaining sauce and grill for 3 to 4 minutes per side or until nicely browned. Serve ribs with reserved sauce on the side.
Bake ribs and make sauce; allow both to cool to room temperature. Cover and refrigerate for up to 2 days. Gently reheat ribs and sauce before grilling.