01 - Preheat oven to 320°F.
02 - Pat the lamb shoulder dry and season generously with salt and pepper.
03 - In a food processor, pulse garlic, rosemary, thyme, oregano, lemon zest, and olive oil to form a paste.
04 - Rub the herb and garlic paste all over the lamb, pressing it into the meat.
05 - Heat 1 tablespoon olive oil in a large roasting pan or Dutch oven over medium-high heat. Sear the lamb shoulder on all sides until browned (about 5-7 minutes total).
06 - Remove the lamb and set aside. Arrange onions, carrots, and celery in the base of the pan. Place the lamb on top of the vegetables.
07 - Pour wine and stock around (not over) the lamb.
08 - Cover the pan tightly with foil or a lid and transfer to the oven. Slow-cook for 4 hours, basting occasionally with pan juices.
09 - Uncover and cook for another 30 minutes to allow the lamb to brown.
10 - Remove from oven and rest, covered loosely, for 20 minutes before serving.
11 - Skim fat from the pan juices and serve the lamb with vegetables and sauce.