01 - Preheat oven to 300°F. Pat the lamb thoroughly dry with paper towels and place in a large roasting pan.
02 - In a small bowl, combine minced garlic, lemon zest and juice, chopped oregano, olive oil, sea salt, and black pepper. Mix well to form a paste.
03 - Rub the marinade generously over all surfaces of the lamb, pressing it into any natural crevices and making small incisions to allow the mixture to penetrate deeper into the meat.
04 - Place halved potatoes, onion wedges, and carrot chunks around the lamb in the roasting pan, distributing them evenly.
05 - Pour the broth and white wine (if using) into the bottom of the pan around the vegetables and meat, being careful not to wash off the seasoning.
06 - Cover the roasting pan tightly with aluminum foil and roast in the preheated oven for 2.5 hours to slowly break down the connective tissue.
07 - Remove the foil and increase oven temperature to 400°F. Continue roasting uncovered for an additional 30 minutes until the lamb develops a golden-brown crust and reaches desired doneness.
08 - Remove from oven and let the lamb rest, loosely tented with foil, for 15 minutes to allow juices to redistribute. Carve against the grain and serve with roasted vegetables and pan juices.