01 - Preheat oven to 325°F.
02 - Combine garlic, rosemary, thyme, oregano, lemon zest, lemon juice, olive oil, salt, and black pepper in a small bowl. Mix thoroughly to form a paste.
03 - Pat lamb shoulder completely dry with paper towels. Rub herb mixture over entire surface, working into crevices and fat layers.
04 - Distribute carrots, onions, and celery evenly across bottom of large roasting pan.
05 - Place seasoned lamb shoulder directly on top of vegetable bed.
06 - Pour white wine and broth around sides of pan, avoiding direct pour over meat.
07 - Cover pan tightly with aluminum foil or lid. Roast for 2.5 hours.
08 - Remove foil and increase oven temperature to 400°F. Roast uncovered for 30 minutes until golden brown and meat pulls away easily from bone.
09 - Transfer lamb to serving platter. Cover loosely with foil and rest 15 minutes before carving.
10 - Skim excess fat from pan juices. Serve lamb with roasted vegetables and strained pan sauce.