Prepare the Lamb Shoulder:

1. Preheat the Oven: Preheat your oven to 300°F (150°C). This low temperature will allow the lamb to roast slowly and evenly, becoming tender and juicy.
2. Prepare the Rub: In a small bowl, combine the olive oil, minced garlic, ground cumin, ground coriander, turmeric, smoked paprika, cinnamon, rosemary, thyme, Dijon mustard, honey, lemon zest, salt, and pepper. Stir until everything is well mixed.
3. Season the Lamb: Pat the lamb shoulder dry with paper towels. Rub the spice mixture generously all over the lamb, ensuring it’s well-coated on all sides. You can also make small slits in the lamb and stuff some of the rub inside for extra flavor. Let the lamb sit at room temperature for about 20 minutes while you prepare the other ingredients.

Roast the Lamb:

4. Sear the Lamb: Heat a large oven-safe pot or Dutch oven over medium-high heat. Once hot, add a little olive oil. Sear the lamb shoulder on all sides for 3-4 minutes per side, until it’s nicely browned. This will help lock in the flavors and juices.
5. Add the Aromatics: Once the lamb is seared, remove it from the pot and set it aside. Add the quartered onion to the same pot and sauté for 2-3 minutes until softened. This will add a great depth of flavor to the dish.
6. Add the Broth: Pour the broth into the pot, scraping up any browned bits from the bottom of the pot. These caramelized bits will contribute to the dish’s rich flavor.

Slow Roast:

7. Roast the Lamb: Place the seared lamb shoulder back into the pot on top of the onions. Cover the pot with a lid or aluminum foil. Transfer the pot to the preheated oven and roast for 5-6 hours, or until the lamb is incredibly tender and the meat pulls away from the bone easily.
8. Check Occasionally: Every 1-2 hours, check the lamb to ensure there’s enough liquid in the pot. If the liquid has reduced too much, add a little more broth or water to keep the lamb moist.
9. Rest the Lamb: Once the lamb is fully cooked, remove it from the oven and let it rest for 15-20 minutes before carving. This allows the juices to redistribute, keeping the meat tender and juicy.

Carve and Serve:

10. Carve the Lamb: Using a sharp knife, carve the lamb into thick slices or shred the meat off the bone, depending on your preference.
11. Serve: Serve the lamb with the roasted onions and a drizzle of the cooking juices. Garnish with fresh herbs, such as rosemary or parsley, and lemon wedges on the side for a bright, zesty finish.