How Long To Cook A Lamb Roast For Perfectly Tender Meat

For many, the key to an ultra-flavorful roast lamb starts with prep the day before. However, that mostly centers around seasoning the meat prior to putting it in your oven.  Cooking the lamb is a different beast, and you want that to be just right — or medium-rare, or well done — for all the usual reasons you want to be precise with red meat (and yes, lamb is red meat). Chief among those are flavor and texture changes and the bacterial risks that come with undercooking. We spoke to Chris Murray, founder and executive chef at The Gourmet Animal, about how you can tell when lamb is ready to leave the heat.

Murray says that, for a standard lamb leg, "I would start at 300 degrees [Fahrenheit] and, depending on the size of the leg, cook for about 1 ½ to 2 hours." However, time is not the ultimate indicator for whether lamb is properly cooked. You also need to know the internal temperature of the meat. 

For that, Murray says you need a meat thermometer which you can insert into the meat. "A probe [is a] must-have in the kitchen," he advises. Once you've checked the temperature, Murray says, "You want the lamb at 125 [degrees Fahrenheit] for medium rare and rising, 130 and rising for medium, and [for] more well done, around 140 and rising." From there, you're ready to move on.

After that initial cook, Chris Murray suggests that you stick the lamb back into the oven and turn the heat up to 375 degrees Fahrenheit until the rub you've added forms a dark crust; at high heat, this may only take 15 minutes. You can achieve that crust in the classic style by using herbs and garlic, or you can try a parmesan crust, like at Longhorn Steakhouse. Murray himself prefers an anchovy and herb rub.

Murray notes that if you're cooking lamb shoulder instead of a leg, "I like it low and slow, and it has to be, or else it's gnarly." He aims for a four- to five-hour cook for a small lamb shoulder, and then waits until the internal temperature reads 190 degrees. He then wraps it in butcher paper and cooks until the internal temperature is between 200 and 205 degrees.

Again, you should do your final checks by using your meat thermometer the right way. Don't place your thermometer on the edge of the meat; you want it to go into the central or thickest part of the cut. Also remember that the lamb's interior will get slightly hotter after leaving the oven. According to Murray, "Remember it needs to rest and will increase a few degrees, as it is still cooking even outside the oven. Let rest for 20 minutes at least, and collect the jus to use in a sauce or a gravy."