Either roast just long enough to serve slightly pink, or reduce the temperature and cook it slowly for darker meat that falls off the bone. Leftover meat from roast lamb is traditionally used in shepherd's pie and the bone can be put to use in a broth. Butterflying a leg of lamb (removing the bone and opening out the meat) is a great technique for barbecuing or grilling a whole leg so that it cooks evenly and quickly. Leg is also sliced and sold as leg steaks for grilling, frying or barbecuing.
