01 - Preheat oven to 300°F. Pat the lamb dry thoroughly and place in a large roasting pan.
02 - In a small bowl, combine garlic, lemon zest and juice, oregano, olive oil, salt, and pepper to create a uniform marinade mixture.
03 - Rub the marinade all over the lamb, massaging it deeply into the meat and any natural incisions for maximum flavor penetration.
04 - Arrange potatoes, onions, and carrots around the lamb in the roasting pan, ensuring even distribution.
05 - Pour broth and wine (if using) into the pan around the vegetables, avoiding direct rinsing of the seasoned meat.
06 - Cover the pan tightly with aluminum foil and roast for 2.5 hours to develop tender, slow-cooked flavor.
07 - Remove foil and increase oven temperature to 400°F. Roast uncovered for 30 minutes or until lamb develops a golden, caramelized exterior and reaches desired doneness.
08 - Let the lamb rest, loosely covered with foil, for 15 minutes before carving to allow juices to redistribute. Serve with roasted vegetables and pan juices.