Rack of lamb is an elegant alternative to more common meat entrees like beef, pork and poultry. Purchase frenched racks, meaning that the ends of the rib bones were stripped of their meat. Frenched racks of lamb cook more evenly and are easier to eat, and they have a nice presentation. Lamb is a versatile dish, supporting a wide variety of recipes and flavors from around the world. However you choose to season it, the process of roasting a rack of lamb in the oven is straightforward and relatively simple.
Take the rack of lamb out of the refrigerator 1/2 hour before cooking it to promote even cooking.
Position an oven rack just below the middle tier so the lamb roasts in the center of the chamber. Preheat the oven to 450 degrees Fahrenheit.
Season or marinate the meat according to your own recipe. Coat it with olive oil and rub it with salt, pepper, rosemary and thyme for a common preparation.
Place the lamb on the rack of a shallow roasting pan. Use a rimmed baking tray lined with aluminum foil if you don't have a roasting pan. Make sure the fatted side of the lamb faces up.
Insert an oven-safe meat thermometer into the center of the meat between rib bones. Make sure the thermometer doesn't come into contact with any bone, as this throws off temperature readings.
Roast the rack of lamb at 450 degrees Fahrenheit for seven minutes. Check that the skin is nicely browned, and give it another minute or two if necessary. Reduce the heat to 350 degrees Fahrenheit.
Cook the lamb until it reaches 120 degrees Fahrenheit if you want it rare. Cook it to 130 degrees Fahrenheit for medium-rare, or to 140 degrees Fahrenheit for medium. Roast the lamb longer if you prefer it cooked more, but the meat will begin to dry out and toughen. Expect the lamb to take between 10 and 20 minutes to cook, depending on how well done you want it, but remember that cooking time always varies. Rely only on temperature readings to know when a rack of lamb is ready.
Rest the rack of lamb for 15 minutes before cutting and serving. Its temperature rises another 5 degrees or so during this time, and its juices settle. Tent it with aluminum foil to hold in its heat.