Lamb Persillé

• 1 loin of lamb, about 4 lb Salt and freshly ground pepper
• Dijon mustard

Season the loin of lamb with salt and pepper, and put to roast in a preheated oven at 425°F for 1 hour 20 minutes, or less if you like it pink.

About 15 minutes before the lamb is cooked, remove from the oven and brush the skin with a thin coati