Heat oven to 325°F. Select a large baking pan to fit ribs in one layer. Line with heavy-duty foil. Place the baking rack (a cake rack works fine) inside a lined pan to keep ribs from resting on the bottom of the pan.

Sprinkle both sides of the spare ribs liberally with onion powder, garlic powder, salt, and pepper. Place seasoned ribs, bone side down, on the baking rack.

Prepare the sauce by combining lemon juice, bottled barbecue sauce, mostarda chiantigiana, balsamic vinegar, and hot sauce (if using) in a small bowl. Stir vigorously until combined. This will make about 3 cups of barbecue sauce.

Pour half of the sauce into a separate container and set aside. Drizzle remaining sauce over the top of the ribs, covering all exposed areas. Cover the pan tightly with heavy-duty foil. Bake for about 90 minutes to 2 hours, or until tender.

Serve spare ribs with reserved barbecue sauce.