How to Make It
Combine the garlic, salt, pepper, thyme and rosemary. With a sharp knife, cut slits all over the lamb, then rub with olive oil. Rub the garlic and spice mixture evenly over the lamb; leave on the counter at room temperature for 1 hour. Preheat oven to 450°.
Place the lamb in a roasting pan, fatty side up, and bake for 30 minutes. Reduce heat to 325° and continue to roast until the lamb reaches desired temperature: 130° for medium-rare, 140° for medium.
Remove from the oven and let rest for 15 minutes before carving. To carve, make cuts every 1/4 inch or so perpendicularly along the leg down to the bone, then cut along the bone to remove everything in one fell swoop. From there, carve off any remaining meat from the bone.