01 - Set oven to 425°F to begin roasting process.
02 - In a small bowl, mix minced garlic, rosemary, thyme, oregano, lemon zest, salt, black pepper, and olive oil to create a paste.
03 - Pat lamb dry and evenly rub herb paste over entire surface, pressing firmly into meat.
04 - Place onions, carrots, celery, and halved garlic in a large roasting pan to form a vegetable bed. Position lamb on top, fat side facing up.
05 - Pour white wine and stock into the pan around the lamb without pouring directly onto the meat.
06 - Roast at 425°F for 20 minutes to develop a crust.
07 - Reduce oven temperature to 350°F. Roast for an additional 60 minutes or until a meat thermometer inserted in the thickest part reaches 135°F for medium-rare doneness.
08 - Remove lamb from oven, transfer to platter, and cover loosely with foil. Allow to rest for 15 to 20 minutes before carving to retain juices.
09 - Skim excess fat from pan juices, strain the liquid, and serve alongside lamb as a flavorful sauce.