01 - Set the oven to 400°F to prepare for roasting.
02 - Combine olive oil, minced garlic, rosemary, thyme, oregano, lemon zest, sea salt, and black pepper in a small bowl to form a paste.
03 - Pat the lamb dry with paper towels and score the fat in a crisscross pattern using a sharp knife. Rub the herb paste evenly over the entire surface.
04 - Scatter the sliced onions, carrot chunks, and celery pieces evenly in a roasting pan to create a bed for the lamb.
05 - Set the lamb atop the vegetable bed and pour the white wine or chicken stock into the pan.
06 - Roast the lamb at 400°F for 20 minutes to sear the exterior.
07 - Reduce oven heat to 350°F and roast an additional 70 minutes, basting halfway through, until internal temperature reaches 135°F for medium-rare.
08 - Remove lamb from oven, tent with foil, and allow to rest for 15 minutes to redistribute juices.
09 - Strain the pan juices and serve as a sauce alongside the lamb.