Pour half of the lemon garlic sauce over the ribs and marinate at room temperature for 30 minutes (or refrigerate overnight).
Season the racks front to back with salt and pepper and wrap individually with foil. Place on a sheet tray lined with foil for easy clean up and bake for 3 hours. Remove the foil and flip the ribs. Apply extra lemon garlic sauce and increase the temperature to 400°F. Roast for 30 minutes longer. Rest before cutting for at least 15 minutes. Serve with extra lemon garlic sauce.