01 - Preheat oven to 300°F.
02 - Combine garlic, rosemary, thyme, oregano, salt, pepper, lemon zest, lemon juice, and olive oil in a small bowl, mixing thoroughly to form a paste.
03 - Pat the lamb shoulder completely dry with paper towels. Rub the herb-garlic paste thoroughly over all surfaces of the lamb, pressing firmly into any crevices.
04 - Arrange sliced onions, carrots, and celery in the bottom of a large roasting pan or Dutch oven. Place the seasoned lamb shoulder directly on top of the vegetable bed.
05 - Pour the white wine and stock around the base of the lamb, avoiding direct pouring over the meat. Cover securely with a heavy lid or double layer of aluminum foil.
06 - Place in preheated oven and roast for 4 to 4.5 hours, basting the lamb periodically with pan juices until meat becomes extremely tender and readily pulls apart with a fork.
07 - Remove lid or foil during the final 30 minutes of cooking to allow the lamb surface to develop a rich golden-brown color.
08 - Transfer lamb to a serving platter and allow to rest for 15 minutes before carving or shredding. Serve accompanied with roasted vegetables and pan juices.