Leg of Lamb Crock Pot Roast

About This Leg of Lamb Crock Pot Roast Recipe

Cooking a lamb leg low and slow in a medley of aromatic and umami ingredients invevitably yields rich tasting, fall-apart tender meat.

This recipe is the type where after a brief initial outlay of work you can blisfully ignore the lamb and let it enjoy the slow cooker and the delicious braising liquid. When you come back, hours later, you will be delighted by the results.

Any lamb lover will instantly appreciate your culinary creation. Those who have not yet warmed up to the virtues of lamb meat might just have an epiphany as soon as they take one succulent bite. 

Boneless or Bone-In Leg of Lamb?

Either cut of lamb will work with this recipe. However we recommend that you opt for a boneless leg of lamb. A boneless lamb leg, regardless of size and weight is much easier to manipulate when it comes to using a slow cooker and this recipe is all about ease and simplicty. 

If you already have a whole bone-in leg of lamb consider this recipe for slow cooked leg of lamb with potatoes. Otherwise make sure you have a large crock pot in which the entire leg fits and brown it in a 450 F oven instead of trying to wrestle it in a frying pan.

If you have a bone-in half leg of lamb, chump end or a shank end, you can work with them as they are smaller and will be easier to handle during searing and each cut will fit comfortably in a crock pot.

Ingredients for Slow Cooker Lamb Leg

Leg of lamb. Preferably boneless, as noted above, it is the best cut. Typically it will weigh about 5 to 6 pounds. This recipe will work with even 8 pounders (they would be from American lamb which is a larger animal).

Olive oil, kosher salt and black pepper. To season and sear the lamb leg and also for the braising liquid base.

Aromatics, herbs and flavorings. You will need: two yellow onions (they give the strongest flavor), a handful of garlic cloves, fresh rosemary (or dried), Worcestershire sauce, anchovy fillets (strongly recommended for the umami flavor they impart, no fishy flavor at all) and Dijon mustard if you opt to make the smooth gravy from the crock pot liquids (do make it, one taste and you will know why).

Red wine and beef broth. With the red wine you will deglaze the braising base. Choose one that is bold and even spicy like a cabernet or a shiraz. The beef broth will thin out the braising liquid and eventually find its way into the gravy. You can substitute with lamb stock if you have it.    

TIP: Other fresh herbs that work with this slow cooker leg of lamb recipe are thyme, oregano and parsley. 

How to Cook Leg of Lamb in Slow Cooker

The three distinct stages of this recipe are described below and the workflow shown with step-by-step pictures. The Recipe Card is at the bottom of this post.

Stage 1. Prepare and sear the meat. Remove the netting and thoroughly pat dry the lamb leg with paper towels. Allow it to reach room temperature and season it with salt and pepper. Heat a large skillet or heavy-bottomed frying pan over medium-high heat, add olive oil and once hot sear all sides of the leg of lamb until they turn golden brown. Transfer the lamb to the crock pot and leave all brown bits and juices in the pan.

It is essential for the surface of the lamb leg to be very dry prior to searing it. Here is why.

TIP: Searing the meat is important not only because it makes the lamb appear more appetizing after hours of braising. The culinary process known as the Maillard reaction gives birth to chemical compounds on the surface of the meat that literally create flavors that would otherwise not take form. The lamb leg becomes much more delicious after it has been nicely browned. To properly brown the surface it needs to be dry. Even though you can skip the searing step we encourage you not to. 

Stage 2. Make the braising liquid. Chop the rosemary really fine, rough chop the garlic and dice the onions. To the same pan where you seared the lamb leg add more olive oil, with the heat at medium. Sauté the onion, garlic and rosemary for just about a minute. Work in the anchovies and Worcestershire sauce. Sauté for another minute and deglaze with the red wine. Be sure to scrape off all the brown bits from the bottom of the pan. They are pure flavor! Simmer to allow the wine to reduce by about half. 

Stage 3. Slow cook. Finally, add the braise base you just prepared to the lamb leg in the crock pot, then follow with the beef stock. Close the lid, turn on your slow cooker and cook until the meat is fork tender. Be patient, enjoy the lovely aromas that will begin wafting a couple of hours into the slow cook and even take a look once in a while... But remember the old adage - 'a watched pot never boils":) 

Once the lamb is ultra tender turn of the slow cooker. When the braising liquid has cooled down a bit you will notice a fair amount of rendered fat floating on its surface. To the best of your ability skim it with a dinner spoon and discard it. You can then carefully lift the leg of lamb out of the slow cooker and place it onto a serving platter. 

How Long Does it Take to Cook Leg of Lamb in Crock Pot?

The short answer is - a long time. 

In truth there is no exact formula that will tell you for this many pounds budget this much time. It all depends on how large the lamb leg you were using, the exact fat content, how warm the center of the meat was before you started searing, the calibration of your slow cooker, whether you go with slow or high heat mode, or a combination of both. 

The best way to tell if the leg of lamb is done is to check it for tenderness. If you can twist off a sizeable chunk with almost no effort by just using a fork it is most likely done. If the meat still resists the fork, then cook it longer. 

For a 6 pound boneless leg as we used for the pictures it took nine hours on slow to achieve the desired tenderness. And we actually left it to cook overnight.

(See the relevant section below for how you can best organize your time depending on when you plan on serving the lamb roast.)

Make a Gravy for Slow Cooker Roast Lamb

To make a smooth gravy first strain the braising liquid through a fine sieve and into a large pan. The larger surface of the pan will help the gravy thicken faster. 

Over medium to medium-low heat bring the liquid to simmer and allow it to reduce. To emulsify it and thicken it further add the Dijon mustard (not only will it create a suave texture but it will bring extra umami notes to the sauce). Simply whisk in the mustard and once the gravy is smooth and as thick as you'd like it to be, transfer it to a warm serving dish. 

If you are impatient you may also add a small amount of slurry to speed up the thickening, but the Dijon mustard helps create a much better consistency overall. 

Serve Slow Cooker Roasted Lamb Leg

When you serve the meat aim for a cozy, rustic family style presentation. It complements the casual vibe of the recipe and helps create an edible centerpiece for your festive table. 

It is a good idea to scatter some fresh greens such as arugula or baby spinach just underneath the leg of lamb and garnish with fresh resemary, maybe a handful of pitted kalamata olives. If you happened to roast some potatoes or perhaps prepared a rice pilaf serve a portion of it next to the lamb to add texture and color to the platter. 

Either pull apart the meat into larger chunks or shred it into smaller pieces. Drizzle some of the gravy to keep it moist and serve the rest of it next to the platter. 

Storage and Reheating

Store leftover lamb meat in an airtight container in the refrigerator. 

To reheat it is best to use a skillet with a bit of olive oil and a bit of water. Reheat over medium heat and place a lid over the skillet (the lamb will not dry out). So prepared the lamb leg is perfect for gyros, wraps or lamb sliders. 

How to Cook This Recipe If You Do Not Have a Slow Cooker

This is a classic braise, so if you do not have a crock pot the solution is simple.

Either use a large braiser or a Dutch oven in which the leg of lamb fits. You can also employ a large roasting pan which you can cover with two layers of foil, tightly wrapped around the edges to create a good seal. A braise like this will be similar to this recipe for Braised Leg of Lamb.