Preheat the oven to 300°F. Season the lamb on both sides with salt and pepper. Pour half of the BBQ sauce over the riblets, front and back, and marinate at room temperature for 30 minutes, or refrigerate overnight
Line a baking tray with foil and place lamb on the tray. Cover with another piece of foil, making sure to seal tightly. Bake in the preheated oven for 3 hours.
Increase the oven temperature to 400°F. Remove the top layer of foil from the riblets and brush the remaining BBQ sauce over the top. Roast for an additional 20-30 minutes or until the riblets are caramelized.
Remove from the oven and let them rest for 10 minutes at room temperature.