1. Pat ribs dry with paper towels. Combine paprika, 1 tbsp of the onion powder, the salt and pepper in a small bowl. Rub onto both sides of ribs. Place meaty side up on a baking sheet fitted with a wire rack. Cover tightly with aluminum foil and refrigerate overnight.
2. Heat oven to 300 degrees F. Transfer foil-wrapped ribs directly to oven and bake at 300 degrees for 3 to 3 1/2 hours or until fork-tender.
3. Meanwhile, melt butter in a small pot over medium-low heat. Add garlic and cook 2 minutes or until softened. Stir in ketchup, honey, molasses, Worcestershire, vinegar, mustard and remaining 1 tsp onion powder. Simmer 15 minutes until sauce thickens. Cover and set aside (see Note).
4. Remove ribs from oven. Increase temperature to 400 degrees F. Remove foil and brush ribs with 1 cup of the sauce. Return to oven, uncovered, and bake at 400 degrees for 10 to 15 minutes until sauce is bubbly.
5. Slice ribs and serve with remaining sauce alongside.