Preheat the oven to 325°F (163°C)
Pat the leg of lamb dry with paper towels
Trim excess fat if needed
Score the fat lightly with a knife
Rub the lamb with salt, black pepper, minced garlic, rosemary, thyme, and olive oil
Place the lamb in a roasting pan or on a rack in a roasting pan
Insert a meat thermometer into the thickest part of the meat, avoiding bone
Roast until the internal temperature reaches:
125°F to 130°F for rare
135°F to 140°F for medium-rare
145°F for medium
Baste occasionally with pan juices if desired
Add vegetables around the lamb if desired
Remove the lamb from the oven when it is 5°F below the target temperature
Tent loosely with foil
Let rest for 15 to 20 minutes
Slice against the grain
Serve with pan juices or sauce