01 - Preheat the oven to 320°F.
02 - Pat the lamb shoulder dry and score the fatty side with a sharp knife. Rub all over with olive oil, salt, and pepper.
03 - In a small bowl, mix garlic, rosemary, thyme, oregano, lemon zest, and lemon juice to form a paste.
04 - Massage the herb mixture into the lamb, pushing it into the cuts.
05 - Scatter onions, carrots, and celery in a large roasting pan to form a bed. Place the lamb shoulder on top, fatty side up.
06 - Pour wine or broth around (not over) the lamb. Cover tightly with foil.
07 - Roast for 2.5 hours. Remove foil, increase oven to 400°F, and roast uncovered for an additional 30 minutes until the top is golden and meat is tender.
08 - Let the lamb rest, loosely covered, for 15 minutes before carving. Serve with roasted vegetables and pan juices.