- 1 Leave the meat at room temperature for 2-3 hours before preparing. Preheat the oven to 300 oF (150 oC).
- 2 Debone the leg of lamb and rub it with salt. Add the pieces of apple, celery, onions, garlic, herbs, and mustard to the cavity where the bone used to be. Tie up the leg of lamb with wire, and brown it in butter in a suitable pan. Roast the leg og lamb on a rack in the oven with a baking tray underneath for two hours or until it has reached a core temperature of 140 F (60 C).
- 3 When the meat has about 45 minutes left, roast the vegetables and apples or until tender and golden brown. Let the meat rest before carving it. Serve the lamb with the root vegetables and some of the leftover meat juices.