Sous Vide Leg of Lamb with Rosemary and Garlic
Perfectly cooked every time with tons of flavor make this recipe a lamb lovers dream
What makes this sous vide leg of lamb recipe so delicious is how the long cooking time and low temperature gives the roast time to develop its flavor while giving it a soft, supple texture.
If you love the bright herb flavors from rosemary and thyme and lamb so tender you can almost cut it with a fork this recipe is for you.
In this Piece
How to Sous Vide a Roast
This is the type of recipe where sous vide stands out as a cooking method, creating a dish that would be almost impossible to make using other techniques.
One big advantage to cooking roasts sous vide is how it locks the juices and flavors in while cooking it long enough to break down the connective tissue in the roast, making it unbelievably tender and juicy. If you’re new to sous vide or would like to learn more read our guide to getting started.
We recommend using a boneless roast in the 3 to 5 pound range that has been butterflied, which is how we usually see them in grocery stores and butcher shops. Butterflying a leg of lamb is pretty easy to do if you’re good with a knife; it’s also something most butchers are happy to do for you.
The advantage to using a boneless vs. bone-in leg is boneless allows you to spread the herbs on the inside of the leg, flavoring the whole thing instead of just the outside, while also making it easier to slice at the end creating a beautiful presentation.
The herb mixture in this recipe gets its Mediterranean flavors from the rosemary, thyme, and garlic. To deepen the lamb’s flavors and bring some contrast to the brightness of the herbs, we add a touch of smoked paprika.
Once the herb mixture has been spread on the lamb, you have the choice of rolling the leg up and trussing it or cooking it as one long piece. If the lamb is being served as a roast, we recommend trussing it, that way it comes to the table looking like a roast. The spiral of herbs in the center looks stunning and makes the dish look harder to make than it is.
To truss the lamb roll the leg up from one side and slip three or four pieces of kitchen twine underneath it. Starting from one end pull the string tight enough to hold the roast together but not so tight that they cut into the lamb.
If the lamb is going to be pulled or sliced into smaller pieces for gyros or bowls, then go ahead and skip the trussing step.
The temperature and time we recommend for cooking a boneless lamb leg sous vide is 134℉ for 6 to 8 hours. Using this time and temperature combination the lamb will turn out medium-rare, taste delicious, and have a supple texture.
If you prefer lamb cooked more rare set the temperature between 130℉ to 132℉, for a roast cooked to a medium level of doneness use 138℉ to 142℉. Since it is being cooked sous vide, the amount of cooking time does not need to be adjusted.
During our testing, we cooked legs anywhere between 5 and 12 hours. On the shorter end, the texture of the lamb made it taste like it wasn’t fully cooked, even though it was, and when it was cooked for more than 12 hours, the lamb started to break down giving it a mealy texture.
Finishing the Lamb
The three most common ways to finish lamb cooked this way are on the grill, in a pan, or the oven.
To finish the lamb on the grill set the temperature to medium and grill the lamb for 5 to 7 minutes per side. The goal is to build up enough char on the outside that it picks up the flavor from the grill without overcooking cooking the inside.
When we’re finishing the lamb on the grill we like to char some lemon slices that can be served with roast to add a little burst of flavor to the finished dish and create a stunning presentation.
To finish the lamb in a pan, use a nonstick pan set over medium heat. It helps to have a relatively large pan and to add some olive oil to the pan before adding the lamb. Let the roast brown for 3 to 5 minutes per side, turning it with a pair of long-handled tongs.
This is the best technique to use if you’d like to serve the lamb with a sauce. The browned bits in the pan are the perfect starter for a pan sauce.
To finish the lamb in the oven, set the temp to 350℉ and roast it for 10 to 15 minutes, turning it halfway through.
This recipe will also work for a lamb shoulder or other types of roasts that you’d like to cook sous vide.
Serving the Roast
The lamb should rest for 5 to 10 minutes after it’s finished cooking. It doesn’t need to sit as long as it would with other cooking methods because sous vide cooking uses lower temperatures which don’t extend the cooking time the way roasting things in the oven does.
Cooking a leg that has been deboned makes it easy to slice the lamb at the table. Just make sure to remember to remove the trussing before serving.
- 4 1/2 pound leg of lamb, boneless
- 2 tbsp rosemary
- 2 tbsp thyme
- 3 cloves garlic, minced
- 1 tsp smoked paprika
- 1 1/2 tbsp olive oil
- 1/2 lemon, sliced
- 2 tsp salt
- 1 tsp pepper
- Start by setting your sous vide water bath to 134℉.
- Prepare the herb mixture by mincing the garlic, rosemary, and thyme and mixing them together with the salt, pepper, smoked paprika, and olive oil. Slice half a lemon into rounds.
- Spread the herb mixture on the lamb, making sure to get it into all the nooks and crannies. Roll the lamb up and slip 3 to 4 pieces of kitchen twine underneath the roast. Truss the lamb by tying the string on the top tight enough to hold the roast's shape.
- Place the lamb in a sous vide bag along with the lemon slices and vacuum-seal everything. Place the leg into the water bath and cook it for 6 to 8 hours.
- Once the lamb has finished cooking, take it out of the water and the plastic bag and pat it dry with a paper towel.
- To finish the lamb grill it on a medium high grill for 3 to 5 minutes per side, turning it as you go. The goal is to add some char to the outside of the lamb without over cooking the inside.
- Let the lamb rest under foil for 5 to 10 minutes before serving.