01 - Preheat your oven to 300°F.
02 - In a small bowl, mix together the garlic, rosemary, thyme, oregano, salt, pepper, lemon zest, lemon juice, and olive oil to form a paste.
03 - Pat the lamb shoulder dry with paper towels. Rub the herb-garlic paste all over the lamb, pressing it into any crevices.
04 - Arrange the sliced onions, carrots, and celery in a large roasting pan or Dutch oven. Place the lamb shoulder on top of the vegetables.
05 - Pour the white wine and stock around (not over) the lamb. Cover tightly with a lid or double layer of foil.
06 - Roast in the preheated oven for 4 to 4.5 hours, basting occasionally, until the lamb is extremely tender and easily pulls apart with a fork.
07 - Remove the lid or foil for the last 30 minutes of cooking to let the lamb brown.
08 - Transfer the lamb to a platter and let rest for 15 minutes before carving or shredding. Serve with the vegetables and pan juices.