Slow Roast Leg of Lamb with Potatoes

Slow-Roasted Lamb

This classic leg of lamb recipe is all about tender, flavorful meat that can literally be pulled apart with a fork but still holds its shape for an appetizing Easter or Christmas holiday worthy presentation. 

We slather a Dijon mustard and rosemary centered lamb leg marinade all over the meat and let a few hours of no fuss, low and slow roasting do their magic. Simplicity cannot be beat as far as lamb is concerned. 

While you do not have to add potatoes and can skip the step, we recommend that you decide in favor of cooking them. They soak up some of the stock with which the roasting pan is filled to provide moist heat for the leg of lamb and are basted by the slowly melting fat and collagen from the meat. The flavor and texture they develop in the process are not to miss!

Ingredients for Slow Cooked Lamb Leg

• Leg of lamb. You can slow roast a bone-in leg of lamb, regardless of cut style (chump or shank on/off) or a rolled boneless leg of lamb. The latter will take less time. 
• Gold potatoes. Either use whole baby Gold potatoes or Yukon golds, thickly sliced. They hold shape their well and are very slow cooking friendly.  
• Chicken stock & lager (optional). To provide gentle moist heat as the meat slowly roasts. We like to add a little bit of German or Czech pilsner to the potatoes because it brings about a nice, herbal touch to the overall flavor. You can substitute with more stock or water. 
• Dijon mustard, fresh rosemary, garlic, salt & pepper and olive oil. See comments below about the marinade.

Lamb Dijon Mustard Marinade

You do not have to marinate the leg of lamb ahead of time - this paste like marinade sticks to the surface, courtesy of the Dijon mustard in it, and as the lamb cooks it is absorbed by the meat and both flavors it and creates an appetizing thin crust.

If you are a fan of strong flavors feel free to make a double batch - use most of the marinade before you begin roasting the lamb leg and apply the reserved part towards the end of the cooking process when you uncover the meat, for a thicker and more flavorful crust.

Step-by-Step Workflow for This Leg of Lamb Recipe

• Prep. It is important to chop the rosemary leaves as small as possible. Mix the marinade ingredients, pat dry the leg of lamb and score the fattiest parts (trim any excess fat, but leave some as it will flavor the meat). Rub the marinade all over. 
• Slow roast. Add chicken stock to a roasting pan, place a roasting rack on top and center the leg of lamb on top, fat side up. Cover with foil, as tightly as you can and roast at 300-325 F for about 3 hours. Check progress (see cooking times below). Add more liquid if needed, cover again and continue slow roasting.
• Add potatoes (optional). Cut the potatoes lengthwise in thick slices or if using baby Gold potatoes halve any larger ones. Add them to the roasting pan when you estimate that there are just under two hours left of slow roasting. Add the lager at this time or a bit of extra stock or water. 
• Finish slow roasting. Slow roast for another hour, then remove the foil and return to oven to brown. The leg of lamb will get a nice crust and the potatoes will finish cooking. Tent lamb leg and allow to rest a few minutes before serving. 

A Slow Roasted Leg of Lamb Gets More Tender the Longer You Cook It

With this recipe you are not stressing over a pink center or internal temperature. Because there is moisture and the meat is covered you are also not concerned about it drying out or the outside browning too fast.

Your singular goal is tender, flavor saturated meat and this is in direct proportion to the time the lamb leg spends roasting at low temperature.

The connective tissues melt turning into liquefied collagen which saturates the meat with flavor. The marrow (when using bone-in leg) melts and flavors the pan juices and potatoes. The slowly melting fat gradually moistens the meat and makes it taste richer and succulent. 

The total cooking time required to slow roast a lamb leg to fork tenderness depends on:

• Size of lamb leg. Bigger takes longer. Budget about 50-60 minutes per pound of lamb, as a guideline, with adjustments per below. 
• Boneless or bone-in cut. The boneless leg will cook faster. The bone-in leg will take longer, especially if it has both the shank and the chump attached. 
• Oven strength/calibration. If you know your oven to be particularly strong adjust the temperature as needed.  

TIP: You will need about 100 minutes for the thick cut gold potatoes to cook through, at about 300-325 F. Add them only after you have checked that the leg of lamb is quite tender already. If you determine that the potatoes are cooked but the lamb could use a bit extra time, simply remove the potatoes and keep warm and let the lamb cook further. 

Serve the Roast Leg of Lamb

To serve first scoop out the potatoes with a slotted spoon and arrange them on an appropriately sized platter. Carefully lift the rested lamb leg (meat will be very tender) and place it over the potatoes. Garnish with a bit of fresh rosemary.

Fresh greens or lettuce based salads make a wonderful companion to the dish as well as this yogurt sauce. 

TIP: Save all the delicious pan juices from the roasted lamb and use them as a sauce. You do not even need to make a gravy with them - simply transfer all the pan liquids to a small bowl or gravy boat and serve it nearby the platter with the leg of lamb.

Reheat Leftover Lamb Leg Meat for Gyros

If you have leftover meat, pull it off the bone and refrigerate or freeze for another meal. We love to make gyros with reheated lamb leg.

Thaw the meat in the fridge overnight (if you froze it), give it a rough shred and reheat in a non-stick pan over medium heat and with an added tablespoon of olive oil. Season with a bit of dried oregano and sauté for a couple of minutes, then add 2-3 tablespoons of water and let it cook a bit longer. As the water evaporates it moistens the tender lamb pieces and they are perfect for folding into a pita bread.