GIGOT D’AGNEAU A LA MOUTARDE (roasted leg of lamb with mustard and herb coating, for six to eight)
one 7 to 8 pound leg of lamb
2 large cloves of garlic
½ teaspoon salt
2 tablespoons Dijon-style prepared mustard
1 tablespoon soy sauce
1-1/2 teaspoons ground rosemary, thyme or oregano
2 tablespoons squeezed lemon juice
¼ cup olive oil or peanut oil
1. Puree the garlic into a small bowl and mash it to a paste with the salt. Whisk in the mustard, soy, herbs, lemon juice, and then the oil, to make a mayonnaise-like cream.
2. Pat the meat dry with paper towels, paint both sides with the mustard coating and place it in a shallow glass dish. (Reserve 2 tablespoons of the mustard coating for the final cooking). Refrigerate, covered with plastic wrap, for at least 1 hour or overnight if possible.
3. Place a rack in the middle of the oven and preheat the oven to 450*. Place the lamb fat side up on a rack in a roasting pan. Set in oven and immediately turn the heat down to 350*. When 45 minutes are up, baste with fat that has accumulated in the bottom of the pan.
4. After 1 hour, start testing for doneness. Any leg of lamb from 5 to 8 pounds will take between 1-1/4 to 1-1/2 hours to reach an internal meat thermometer reading of 125* (insert thermometer into the thickest part of the leg – without touching the bone). Paint it with the reserved mustard coating about 20 minutes before the lamb is done.
120* very rare
125* rosy rare
130* medium rare
140* medium – the official “safe” temperature where all harmful bacteria are killed
5. As soon as the lamb is done, remove it from the oven and place on a carving board or platter. Discard any trussing strings. Let it stand for between 15 and 25 minutes before carving so that its juices can retreat back into the meat. The internal temperature of the lamb will rise somewhat during this process.
6. If the lamb must wait longer still, tent aluminum foil over it to keep it warm. You can use a warming oven, but make sure the temperature does not exceed 120* or the lamb will continue to cook. You can keep it warm for an hour or more.
NOTE: This coating works equally well for a grilled butterflied leg of lamb. Paint it with the reserved mustard coating when you turn it over the final time.
adapted from Julia Child, The Way to Cook