01 - Set the oven temperature to 300°F.
02 - Pat the leg of lamb dry with paper towels. Using a sharp knife, make deep slits evenly across the surface of the meat.
03 - Stuff the garlic halves and some of the rosemary into the slits of the lamb.
04 - In a small bowl, mix olive oil, lemon zest, lemon juice, remaining rosemary, thyme, kosher salt, and black pepper. Rub this mixture thoroughly over the entire leg of lamb.
05 - Place the carrots, onions, and baby potatoes in a large roasting pan and position the lamb on top.
06 - Pour the dry white wine or chicken broth into the base of the roasting pan.
07 - Cover the roasting pan tightly with aluminum foil and roast in the preheated oven for 2.5 hours.
08 - Remove the foil, increase the oven temperature to 400°F, and roast uncovered for an additional 30 minutes until the lamb is browned and vegetables are tender.
09 - Transfer the lamb to a serving platter, loosely cover with foil, and let it rest for 15 minutes before carving. Serve alongside the roasted vegetables and pan juices.