Sous Vide Leg of Lamb with Rosemary and Garlic
What makes this sous vide leg of lamb recipe so delicious is how the long cooking time and low temperature give 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, try this recipe the next time your craving perfectly cooked lamb.
This piece includes info on picking the right leg, how to sous vide it, using fresh herbs to create Mediterranean flavors that pop, and delicious side dishes that compliment the roast.
Bone-in vs. Boneless Leg of Lamb
There are a few things to decide when choosing a leg of lamb. The first is bone-in or boneless; most of the time, we recommend choosing bone-in roasts, especially when it comes to beef or pork. The bone helps to add flavor and moisture, it can be used as the base for stocks and soups, and the roasts are usually less expensive than deboned ones.
It’s a bit different with lamb legs, where it can be hard to cut nice slices of meat from around the bone.
It’s also a cut that starts out so rich and flavorful that the bone doesn’t add much to the overall flavor; although toss a leftover one into a pot of white beans along with some garlic, and you’re halfway to a fantastic meal.
When it comes to sous vide, especially if the roast is being served as the centerpiece for a nice dinner, we recommend using a boneless roast in the 3 to 5 pound range that has been butterflied. This is the size most commonly found in butcher shops and grocery stores.
Butterflying is relatively simple if you’re good with a sharp knife; it’s also something most butchers are happy to do for you.
Using a butterflied leg lets the cook spread herbs on the inside of the leg, flavoring the whole cut instead of just the outside. It also makes it easier to cut large thin slices, creating a beautiful presentation. That being said, this recipe will work with bone-in or boneless.
Always look for a leg with a bright red color, a fresh smell, and doesn’t look or feel clammy to the touch.
A good rule of thumb is to plan for 1/2 pound of meat per person with a boneless leg and 3/4 of a pound with a bone-in leg. When it comes to size, whole legs tend to be in the 10 to 12 lb range and can be a challenge to sous vide because they don’t fit in standard size bags.
If you’re having a large gathering and need more lamb than comfortably fits in a standard sous vide bag, making a second roast of moderate size is often easier than trying to jerry-rig a setup to cook a large one.
Another of our favorite ways to cook a leg of lamb is to spit-roast it on the grill using a rotisserie.
How to Sous Vide a Leg of Lamb
What makes sous vide such a good choice for cooking a leg of lamb is how it infuses the meat with the flavors from the fresh herbs while keeping everything tender and juicy.
The challenge of cooking a roast like this in the oven is that the meat on the outside can become overdone and tough by the time the center is cooked all the way through. Sous vide overcomes this by cooking the entire roast at the same temperature from edge to edge.
If you’re interested in learning more about this innovative cooking method, read What is Sous Vide Cooking and Why it Works.
Seasoning the Lamb
The herb mixture in this recipe gets its Mediterranean flavors from fresh rosemary, thyme, and garlic. To deepen the lamb’s flavor and bring some contrast to the brightness of the herbs, we add a touch of smoked paprika and lemon slices.
Once the leg has been seasoned, it can be rolled up and trussed or cooked as a single long piece.
If the lamb is being served as a roast, we recommend trussing it, so it comes to the table shaped like a traditional roast. Also, trussing creates a spiral of herbs in the center that looks stunning when sliced and makes the dish look harder to make than it is.
If the lamb is going to be pulled or sliced into smaller pieces for gyros or bowls, skip the trussing step. The leg can be prepped a day ahead of time.
Prepping the Roast
Once the leg and herbs have been prepped, slather the herb mixture on the inside of the leg.
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 it cuts into it.
A pro tip on trussing is tying the strings from the outside and working your way towards the center. This helps the roast keep its shape as it cooks.
Seal the lamb in a plastic pouch using a vacuum sealer before placing it in the water bath. The water bath should be in a container large enough to allow good circulation and be preheated to the target temperature using an immersion circulator. Here is a great one that has a lid to help prevent evaporation.
If a vacuum sealer isn’t available, the water displacement method can be used, which is where the roast goes into a large freezer bag and is lowered into the water with a straw inserted into the bag to let the air escape.
One of the secrets to great sous vide cooking is using a vacuum sealer to put the food under pressure as it’s sealed in plastic. This helps force the herbs and spices in the bag into the food being cooked and ensures that the whole item is cooked in its juices.
The recommended temperature for cooking a leg of lamb leg sous vide is 134℉ (56℃) 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.
The temperature chart below is the same one we use with our Sous Vide Rack of Lamb recipes. Since the lamb is being cooked sous vide, the amount of cooking time remains at 6 to 8 hours and does not need to be adjusted to reach the different levels of doneness.
| Type | Temp | Description |
| Rare | 116℉ – 124℉ | 46℃ – 51℃ | Cool red center, soft to the touch |
| Medium-Rare | 125℉ to 135℉ | 52℃ – 57℃ | Warm red center, firmer with a bit of spring |
| Medium | 136℉ to 144℉ | 58℃ – 62℃ | Pink all the way through & firm to the touch |
| Medium-Well | 145℉ to 154℉ | 63℃ – 67℃ | Gray and brown all the way through, very firm |
| Well Done | 155℉ plus | 68℃ plus | Dark gray and very firm |
During our testing, we cooked legs at a range of times 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 had reached the internal target temperature.
When it was cooked for more than 12 hours, the meat started to break down, giving it a mealy texture.
Finishing a Sous Vide Leg of Lamb
The three most common ways to finish lamb cooked sous vide are on the grill, in a pan, or in the oven. They are all variations on the reverse sear technique, where the protein is seared after being cooked.
Grill – To finish the lamb on the grill, preheat the grill to medium to medium-high and grill the lamb for 5 to 7 minutes per side. We love using the grill to finish a leg because it adds char on the outside and depth and complexity 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 look great on the platter.
Pan Seared – To finish it on the stovetop, use a good skillet set over medium-high heat. Large preheated cast iron skillets are particularly effective. It also helps to add a little olive oil to the pan before searing.
The roast should be seared for 3 to 5 minutes per side. The easiest way to turn it is with a pair of long-handled tongs.
This is the best technique to use if you want to serve the lamb with a pan sauce. The browned bits in the pan are the perfect starter for a sauce made with a little white wine, butter, and lemon juice.
Oven – To finish it in the oven, preheat the oven to 350℉ (177℃) and set the leg on a roasting or broiler pan for 10 to 15 minutes, turning it halfway through.
This recipe and basic technique will work for just about any lamb roast cooked sous vide.
What to Serve with Leg of Lamb
Once the leg has finished cooking, it should rest for 5 to 10 minutes before slicing. It doesn’t need to sit as long as it would with other cooking methods because sous vide uses lower temperatures which don’t have the same type of carryover cooking the way roasting things in the oven or on the grill 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.
This recipe infuses the tender meat with bright Medeterrian flavors that can easily make this dish the star of a nice dinner party or the centerpiece of a holiday dinner.
When serving this recipe at dinner parties, we like to pair it with a creamy Herb Risotto, Roasted Carrots with Rosemary and Fennel, or Great Northern Beans with Roasted Garlic. For dessert, try this Rhubarb Cake.
The meat can also be sliced thin or pulled apart and served on gyros or in rice bowls filled with fresh vegetables.
When we’re serving it this way, we like to make a batch of homemade Tzatziki and serve it with a side of Couscous with Red Peppers and Feta Cheese.
No matter how it is served, the lamb pairs well with bright white wines like sauvignon blanc or white bordeaux that have been thoroughly chilled.
The simplest way to reheat the lamb is in a 350℉ (177℃) oven. If it’s been sliced, place it in a baking dish, cover with foil, and heat for 10 to 15 minutes.
If it’s unsliced, place it in a baking dish, cover with foil, and heat for 25 to 35 minutes taking it out when it’s reached the desired internal temperature.
Ingredients
- 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 virgin olive oil
- 1/2 lemon, sliced
- 2 tsp kosher salt
- 1 tsp black pepper
Instructions
- Start by setting your sous vide water bath to 134℉ (56℃).
- Prepare the herb mixture by mincing the garlic cloves, rosemary, and thyme and mixing them with salt, pepper, smoked paprika, and olive oil. Slice half a lemon into rounds.2 tbsp rosemary, 2 tbsp thyme, 3 cloves garlic, 1 tsp smoked paprika, 1 1/2 tbsp virgin olive oil, 1/2 lemon, 2 tsp kosher salt, 1 tsp black pepper
- Spread the herb mixture on the inside and outside leg, getting it into all the nooks and crannies.4 1/2 pound leg of lamb
- Roll the lamb back 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 a few 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.
- To finish the lamb on the grill, place it on a preheated medium-high grill for 5 to 7 minutes per side, turning it as you go. The goal is to add some char to the outside without overcooking the inside.
- Let the leg of lamb rest for 5 to 10 minutes before cutting it into thin slices. Serve with some charred lemon slices on the side.
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Mark is an experienced food writer, recipe developer, and photographer who is also Umami’s publisher and CEO. A passionate cook who loves to cook for friends, he can often be found in the kitchen or by the grill testing new recipes.
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