A rack of lamb or carré d’agneau (though this may also refer to other cuts) is a cut of lamb cut perpendicularly to the spine, and including 16 ribs or chops. At retail, it is usually sold ‘single’ (sawn longitudinally and including the 8 ribs on one side only), but may also be sold as a “double rack of lamb”, with the ribs on both sides. Rack of lamb is usually roasted, sometimes first coated with an herbed breadcrumb persillade. The tips of the bones are sometimes decorated with paper frills called manchettes.1
Preheat oven to 425 degrees. Season lamb with salt and pepper. Heat oil over high heat in a large ovenproof skillet and sear lamb, fat side down, until dark brown, about 6 minutes.
Remove lamb from skillet, and discard fat. Return lamb, seared side up, to pan, and roast in oven until a thermometer inserted in center reaches 130 degrees, 15 to 17 minutes. Let lamb rest on a cutting board, loosely tented with foil.
Pour out excess fat from skillet, and place over medium-high heat. Add wine, and simmer, stirring and scraping up browned bits, until reduced by two-thirds, about 2 minutes. Whisk in stock, mustard, and molasses, and simmer until thickened, about 8 minutes. Carve lamb into individual chops, and serve with sauce.