Preheat oven to 400 degrees. In an ovenproof skillet, heat 1 tablespoon of oil until shimmering. Season a 2 1/2 pound frenched rack of lamb with salt and pepper. Add the lamb to the pan, fat side down and cook over moderately high heat until browned, 3 minutes. Turn the lamb fat side up and cook for 2 minutes longer. Transfer the skillet to the oven and roast the lamb for 20 minutes, until an instant read thermometer inserted in the center of the meat registers 125 degrees for medium-rare. Transfer the lamb to a carving board and let rest for 10 minutes. Pour off the fat in the skillet and make the pan sauce.

Mustard Shallot Sauce
In the skillet the lamb was cooked in, cook 2 sliced shallots in 2 teaspoons oil until soft. Add 1/4 cup white wine and simmer for 2 minutes. Add 1/4 cup chicken stock and bring to a simmer. Off the heat, add 1 tablespoon whole grain mustard and 2 teaspoons each of Dijon mustard and thyme leaves.

Food and Wine, February 2011, page 82