01 - Set the oven temperature to 320°F.
02 - Pat the lamb shoulder dry; rub evenly with olive oil, salt, and black pepper.
03 - Make small slits all over the lamb using a sharp knife and insert halved garlic cloves into them.
04 - Place onions, carrots, and lemon wedges in a large roasting pan, then position the lamb shoulder on top.
05 - Distribute rosemary and thyme sprigs around and atop the lamb.
06 - Pour white wine and stock into the pan surrounding the lamb without pouring over it.
07 - Cover the pan tightly with foil or a lid and roast for 4 hours, basting once or twice with pan juices.
08 - Remove cover, increase oven temperature to 400°F, and roast uncovered for 20 to 30 minutes until the top crisps.
09 - Remove from oven and let rest, loosely covered with foil, for 20 minutes.
10 - Slice or shred the lamb, garnish with fresh parsley, and serve alongside the roasted vegetables and pan juices.