01 - Set oven to 400°F.
02 - Combine olive oil, garlic, rosemary, thyme, oregano, lemon zest, salt, and pepper in a small bowl and mix into a paste.
03 - Pat lamb dry and score fat in a crisscross pattern using a sharp knife.
04 - Rub the herb paste evenly over the entire lamb.
05 - Scatter onions, carrots, and celery in a large roasting pan to form a vegetable bed.
06 - Place lamb atop the vegetables and pour white wine or stock into the pan.
07 - Roast lamb at 400°F for 20 minutes.
08 - Reduce oven to 350°F and roast for an additional 70 minutes or until internal temperature reaches 135°F for medium-rare.
09 - Baste lamb with pan juices halfway through the cooking time.
10 - Remove from oven, cover loosely with foil, and let rest for 15 minutes before carving.
11 - Strain pan juices and serve alongside the lamb.