Smoked Leg of Lamb with Mustard Mint Sauce

Saturday, March 26, 2016

Disclaimer: I received compensation and a product sample for this post. The opinions and text are all mine. 

I'm back with another lamb recipe for the spring holidays! I've been excited about my partnership with The American Lamb Board this year, so this was a fun post to work on. Last summer, I spent a lot of time learning to grill and smoke meats outdoors. Now that our weather is returning to tolerable temperatures, it's a great time to get back out there and continue the adventure. As many of you may remember, we smoked our turkey for Thanksgiving last year. It turned out to make the rest of the holiday cooking easier, as it freed up the oven. When I received this beautiful leg of lamb to play with, I knew that smoking it would make for an interesting spring roast. This was a great, low-carb and Whole 30 compliant weekend dinner and would be a fabulous alternative to traditional spring roasts.

I chose to work with a boneless leg of lamb, which is the leanest cut of American lamb but still has great marbling within. I've always loved the robust flavor of lamb, and definitely preferred this over the beef roasts I have cooked in the past. Because the bone was removed, I was able to open up the cut of meat and slather it with a garlicky mustard marinade inside. The salt in the marinade helped to season the meat from within, for more flavorful meat. All in all, it was a really easy process and took about half a day, not including the overnight marinade. The most challenging part was really just tying the roast up with butcher's twine. I totally did a hack job but my technique is getting slightly better. This video tutorial from The American Lamb Board helped a bit with that part (the roast is tied at the 1:45 mark) but the whole video was helpful for tips in working with a leg of lamb.

My dad helped me by setting up the Weber Smokey Mountain Barbecue Smoker with applewood. The tied leg of lamb smoked for about three and a half hours total. I let it rest for thirty minutes and then finished it over direct heat on the grill to crisp the outer layer of skin, an optional step. You can use any smoker with this recipe, just follow your manufacturer's directions for the ideal setup. I tend to peruse the bbq and smoking forums online whenever I try something new, and found great tips for our smoker at the Amazing Ribs site.

If you don't have a smoker to use and still want to work with a boneless leg of lamb in a similar way, you can roast it in the oven (use a roasting pan with a rack) at the same low temperature. You obviously won't get the benefits of the smoke for flavor, but you can achieve a juicy, medium rare roast for the holidays.

Smoked Leg of Lamb with Mustard Mint Sauce

2 tbsp creole or dijon mustard
8 cloves roasted garlic* (see note)
1 tbsp smoked paprika
Zest and juice of 1 lemon
1 tsp crushed red pepper flakes
1 tbsp cracked black pepper, more as needed
2 tbsp kosher salt, more as needed
Olive oil, as needed
7 to 8 lb boneless leg of lamb
4 tomatoes, sliced into wedges (optional)
2 onions, sliced (optional)

For the Mustard Mint Sauce:
1/2 cup chopped mint leaves
1/4 cup parsley
2 cloves roasted garlic* (see note)
1/4 tsp crushed red pepper flakes
Juice and zest of 1 lemon
2 tbsp creole or dijon mustard
1/4 cup olive oil, more as needed
Kosher salt, to taste
Cracked black pepper, to taste

Active Time: 1 hour
Total Time: 8 hours (up to 24 with an overnight marinade)
Yield: Serves 8 generously with leftovers
Special Equipment: Smoker and/or grill, food processor or mortar & pestle (optional)

*Note: You can purchase peeled, roasted garlic cloves or just make your own ahead of time. In a small ovenproof dish add the peeled cloves from two whole heads of garlic. Cover with olive oil. Roast at 300°F for about 45 minutes or until garlic is fork tender. I just do this whenever I have something else in the oven around the same temperature. The olive oil gets infused with garlic so it can also be used in the recipe. Store leftovers in tightly closed jar, topped off with additional olive oil if needed.

To make the marinade, add the mustard, roasted garlic, smoked paprika, lemon juice and zest, red pepper flakes, black pepper and salt to a small bowl. Mash the garlic into a paste with the other ingredients. Add just enough olive oil to make it a spreadable consistency.

Boneless legs of lamb usually come wrapped in a netting to keep the roast tied. You'll want to remove that first to open up the lamb. Spread the marinade all over the interior of the meat, getting into all the crevices. You can roll it up and tie the roast now, or if you have room in the fridge just transfer the untied lamb to a large bowl wrapped in plastic to marinate for at least 4 hours, preferably overnight. (I tried this both ways and preferred the longer marinating time.)

The next day, tie up the roast into a uniform shape, securing with butcher's twine. I wanted to smoke some tomatoes and onions to use in a side dish along with the lamb, so I opted to put everything in an aluminum pan. You can do that, or roast the lamb alongside potatoes for something more traditional. If you want to place the tied lamb leg right on the racks, just be aware that fat will drip as the lamb smokes. To monitor the internal temperature of the lamb as it smoked, I inserted a probe thermometer into the thickest part of the meat. I definitely recommend using one of those when you're slow cooking anything, whether in the smoker, grill or oven, because it allows you to keep an eye on the temperature remotely. Especially with a smoker, where the goal is to keep the temperatures low and steady, constantly opening the smoker up to check on a piece of meat can cause big fluctuations in heat.

As I mentioned above, we used applewood to smoke the lamb. It's best to use a fruity mild wood so as not to overpower the flavor of the lamb. The lamb smoked for about three and a half hours at 225°F, until the internal temperature read 130°F. Leg of lamb is best served medium rare, so pulling the roast out a little early leaves some room for the residual heat to carry the temperature up a bit without overcooking it. Once the lamb was removed from the smoker, I let it rest for 30 minutes.

Meanwhile, I made the mustard sauce by combining the mint, parsley, garlic, red pepper flakes and lemon zest in my mortar and pestle with a splash of olive oil, grinding and crushing the herbs until silky. I transferred that to a bigger bowl, stirring in the lemon juice, mustard and additional olive oil to make the sauce, then seasoned with salt and pepper. I'm a little obsessed with the way a mortar and pestle brings out the flavors in my herb based sauces these days. If you don't have one, you can combine all the ingredients in a food processor and pulse to combine, adding the olive oil at the end. Or, just very finely mince the herbs and smash the garlic by hand before mixing the remaining ingredients. Lots of options, so just do what works. 

After the lamb rested, I finished it off on the grill over direct heat to crisp the skin on all sides. That just took about 5 minutes total. Broiling the lamb for a few minutes would be an alternate method, just be careful not to overcook it after your work to perfectly smoke it.

The lamb was ready to slice and serve immediately, since it had already been rested. I did nice thick slices, serving with the mustard mint sauce and some of the smoked tomatoes.

I used the rest of the tomatoes to make a quick side dish, sauteed with fresh spinach.

One of the best parts of having such a large roast was all the leftovers! Over the next couple days, the smoked leg of lamb was great eaten alone or sliced thin for sandwiches, with some of that mustard mint sauce of course. My son preferred to quickly warm his in a pan for a couple minutes, while I liked it cold, with excess fat pulled off. 

Give the smoker a run if you'd like to enjoy a nice leg of lamb for your next holiday dinner! It turned out to be an easy, reliable method of cooking the lamb perfectly and can be adapted for any menu you have in mind. To find out more information about entertaining with American lamb this spring, check out The American Lamb Board's website!

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