Get all the preparation tips and cooking times you need to roast lamb that's crusty on the outside, tender and juicy on the inside. We'll share tips for how to choose the right cuts of lamb, how to season it, and the ideal roasting times and temperatures.
Choosing the Right Cuts
The leg and rack are the most tender cuts of meat on a lamb, and are at their best when roasted. Roasting is a "dry heat" cooking method, meaning that you do not add any liquid to the meat as you cook it.
Leg of Lamb
You can purchase leg of lamb bone-in or boneless. A whole leg of lamb often includes the shank portion, but since the shank does not take well to the dry heat of roasting, it's best to buy the leg without the shank. You can also buy a half leg of lamb; the butt-end of the leg will be the meatiest and most tender.
More: Get recipes for leg of lamb.
Rack of Lamb
Rack of lamb is the cut with the rib bones or chops. This succulent roast is often served "Frenched," with the fat and meat trimmed from between the ribs and the bones scraped clean and protruding outward. Your butcher should be able to prep the roast for you; remember to ask for the meat trimmings if you want to make soup later on. When two or more racks of lamb are tied together to form a circular roast, it's called a crown roast.
Seasoning the Meat
Lamb is flavorful enough on its own that it doesn't need much seasoning, yet robust enough that it pairs beautifully with any number of boldly flavored seasonings, like rosemary, oregano, marjoram, thyme, lemon zest, cumin, coriander, mint, and garlic.
How to season lamb:
- Trim some of the excess fat and any silver skin;
- Chop up herbs/seasonings and rub the mixture evenly over the surface of the meat;
- Wrap the coated meat tightly in plastic wrap and refrigerate overnight for the best flavor.
Another popular way to season a roast is to make small incisions in the surface of the meat and push slivers of garlic and sprigs of herbs into the slits. You can do this right before you begin roasting or a day ahead for more intense flavor.
When you're seasoning the lamb, don't salt it until just before cooking; salt can draw moisture out of the meat.
With this roasted lamb recipe, there's no need for mint jelly on the side. Because Chef John roasts the mint flavor right into the crust! And instead of the jelly, Chef John serves his rack of lamb with a slightly sweet vinaigrette. You’ll also get a great tip for getting your lamb to cook evenly. See how it's done!
Roasting Lamb: Temperatures and Times
Before roasting lamb, remove it from the refrigerator and allow it to sit at room temperature for at least 30 minutes. A piece of meat at room temperature will roast more evenly.
Use a roasting rack to ensure even browning and heat circulation around the meat.
How to determine the ideal roasting temperature and time for lamb. The amount of fat that your lamb has on the outside and marbled through the middle will determine the cooking time and temperature:
- Roast leaner cuts in a hotter oven: A hot oven gets leaner cuts of meat nicely browned on the outside before they become overcooked and dry in the middle. For a lean piece of meat, cook at 450 degrees F (230 degrees C) for the first 15 minutes, then turn the temperature down to 350 degrees F (175 degrees C) to continue roasting — the meat will take about 25 minutes per pound to reach medium rare.
- Roast fattier pieces of lamb longer and at lower temps: For a fattier piece of meat, roast at 325 degrees F (160 degrees C) for a longer period of time, allowing the fat to slowly melt and bathe the roast in its own juices. Meat cooked with this method will take about 30 minutes per pound to reach medium rare.
The most accurate way to determine doneness is with a meat thermometer:
- 110 degrees F (42 degrees C) is rare
- 120 degrees F (58 degrees C) is medium-rare
- 145 degrees F (68 degrees C) is medium-well
The USDA recommends cooking roasts to 145 degrees F. Avoid cooking your lamb beyond this temperature as the meat can become dried out and tough.
Rest Your Roast
Once your roast is within 10 degrees F (5 degrees C) of its ideal cooked temperature, remove from the oven, place a foil tent loosely over it, and let rest for 15-20 minutes. As the meat rests, the internal temperature will increase by several degrees, the muscle fibers will relax, and the juice that has come to the surface of the meat during cooking will begin to return to the center. A well-rested piece of meat will be more tender and retain its juices better when you slice it.