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You can make a tender and juicy Roasted Boneless Leg of Lamb with just 15 minutes of prep and less than 2 hours of roasting time. A beautiful way to feed a hungry group of people, it’s a roast that’s perfect for your Easter table, but also wonderful for family meals and dinner parties all year long.

Roasted Boneless Leg of Lamb served on a gray oval platter

Most of us are used to cooking chicken, pork and beef, but cooking a leg of lamb can be daunting. But I promise that if you follow this simple recipe, you’ll be rewarded with a mouthwatering meal with very little effort.

Ingredients You Need To Make Roasted Boneless Leg of Lamb

Roasted Boneless Leg of Lamb Ingredients on a white marble board
  • Olive Oil: Good, extra-virgin olive oil.
  • Dijon mustard: I recommend creamy.
  • Garlic: Firm, plump cloves with smooth, silvery skin.
  • Herbes de Provence: Or a blend of dried herbs and minced fresh rosemary.
  • Kosher Salt: Quantity based on Diamond Crystal brand kosher salt – note that other brands such as Morton are almost twice as salty, so adjust the amount accordingly or to taste.
  • Black Pepper: Ideally freshly ground.

Keys to Success

It all starts with prepping your lamb leg, unrolling it and trimming off excess fat and tendon. Then you’ll massage it, inside and out, with a fragrant blend of olive oil, fresh garlic, Herbs de Provence and creamy Dijon mustard before rerolling and securing with kitchen twine. In the oven it will tranform into a succulent boneless lamb roast with a crisped, herbaceous crust.

If you’re fortunate enough to have leftovers, make lamb sandwiches (extra mustard for me!) or breakfast hash (like this Corned Beef Hash).

Roasted Boneless Leg of Lamb sliced and served on a gray oval platter

FAQ

What can you season lamb with?

Lamb pairs well with many seasonings, but these are among the best: garlic, mint, mustard, onion, parsley, black pepper, rosemary, and thyme.

What is Herbes de Provence?

Herbes de Provence are a dried herb blend often used in French cuisine. The herb blend varies by brand, but often includes rosemary, thyme, marjoram, savory, oregano, and sometimes lavender (though it wasn’t in the original French version). Some blends also include fennel seed, bay leaf, and/or tarragon.

Which is better bone-in or boneless leg of lamb?

Though both are delicious, boneless leg of lamb has some distinct benefits. It cooks faster and is easier to carve. It fits easily into roasting pans and, for the weight you get more meat (though you’ll likely pay more per pound than a bone-in leg of lamb).

Can I use fresh rosemary instead of dried?

Yes, absolutely. In fact fresh rosemary has more flavor and the leaves are less woody than their dried counterparts. For this recipe, there is some rosemary in the dried herb blend, but you can embellish the herb rub with minced fresh rosemary leaves for more robust flavor.

How do you cook lamb so it’s tender?

The key to tender lamb is to not overcook it. Use an instant read thermometer to be sure that you pull it from the oven at the proper time, 10˚F before it reaches your desired temperature as the cooked meat’s internal temperature will rise after you remove it from the oven). Target temperatures: Medium-Rare 145˚F, Medium 160˚F, Well-Done 170˚F.

What to Serve Alongside

How to Make Roasted Boneless Leg of Lamb

Step 1: Whisk together Dijon herb paste ingredients.

mustard herb paste

Step 2: Untie and unroll boneless leg of lamb. Trim away excess fat from both sides of the leg. Rub underside with 1/3 of herb paste. Re-roll roast and secure at ends and center with kitchen twine. Rub top with remaining herb paste and place on oven safe baking rack set inside foil lined rimmed baking sheet.

Step 4: Roast in a preheated 425˚F oven for 15 minutes. Reduced heat to 350˚F and roast 1 to 1 1/2 hours more, until an instant read or meat thermometer inserted into the center reads 135˚F for medium rare. Remove roast and let stand 15-30 minutes before slicing. Slice and serve.

Roasted Boneless Leg of Lamb on rack in rimmed baking sheet

Recipe Video

Roasted Boneless Leg of Lamb

5 from 17 votes
Prep: 15 minutes
Cook: 1 hour 45 minutes
Total: 2 hours 15 minutes
Course: Main Course
Cuisine: Mediterranean
Calories: 255
Servings: 10 people
Juicy flavorful leg of lamb made with just 15 minutes of hands-on time!

Ingredients  

  • 5 1/2 pound boneless leg of lamb

For the Dijon Herb Paste

  • 1/4 cup extra virgin olive oil
  • 2 tablespoons Dijon mustard
  • 4 medium garlic cloves minced
  • 2 tablespoons dried Herbes de Provence (recipe note #1)
  • 1 tablespoon kosher salt (recipe note #2)
  • 1/2 teaspoon freshly ground black pepper

Instructions 

  • Place an oven safe rack inside a rimmed baking sheet lined with foil (for easy cleanup).
  • If lamb roast is tied, untie and unroll. Trim away thick areas of fat and tendon from the top and bottom of the roast, leaving a thin layer of fat on top.
  • Whisk together all Dijon Herb Paste ingredients in a medium bowl until they emulsify into a uniform paste.
  • Spread 1/3 of herb paste all over underside of roast. Roll roast back up into its original shape and snugly tie in the center and at both ends with three lengths of kitchen twine. Rub outside all over with remaining herb paste. Transfer roast, seam side down, to rack on prepared baking sheet and let stand at room temperature while the oven preheats.
  • Preheat oven to 425°F.
  • Roast lamb in hot oven for 15 minutes. Reduce heat to 350˚F and cook until an instant read thermometer inserted into the center registers 135˚F (for medium rare – the temperature will rise as the roast rests before slicing), 1 to 1 1/2 hours. Transfer roast to cutting board; let stand 15-30 minutes before slicing.
  • Snip twine with kitchen shears; remove and discard. Slice roast thinly (about 1/4-inch) and arrange on platter. Serve.

Notes

  1. If you love the combination of rosemary and lamb, use 1 tablespoon of Herbes de Provence and 1 tablespoon of minced fresh rosemary. And / or to add brightness to herb paste, stir in 1 teaspoon of fresh lemon zest or more.
  2. Quantity based on Diamond Crystal brand kosher salt – note that other brands such as Morton are almost twice as salty, so adjust the amount accordingly or to taste.

Nutrition

Calories: 255kcal | Carbohydrates: 1g | Protein: 33g | Fat: 13g | Saturated Fat: 3g | Cholesterol: 101mg | Sodium: 830mg | Potassium: 471mg | Fiber: 1g | Sugar: 1g | Vitamin A: 33IU | Vitamin C: 1mg | Calcium: 29mg | Iron: 4mg

Nutrition information is automatically calculated, so should only be used as an approximation.

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50 Comments

  1. David Moonan says:

    5 stars
    Recipe is solid, however I couldn’t
    Couldn’t believe what I was reading with regards to untying roast, trimming and retie back. First off that’s a total waste of time and a super mess!! The butcher absolutely should have done the trimming first time around. Secondly, few people probably actually know how to
    BRT a roast.

    1. Marissa Stevens says:

      Hi David! It’s less about trimming and more about smearing the mustard-herb paste on the inside of the roast, which is key to the flavor in this recipe. On a large cutting board, it really isn’t much mess to unroll and then roll and retie it.

  2. Margerat Wong says:

    5 stars
    This recipe is fantastic the lamb came out so tender & tasty. Bon Appetit

    1. Marissa Stevens says:

      That’s wonderful to hear, Margerat! Thank you for letting me know.

  3. Cardi says:

    5 stars
    Used this recipe last night and it was amazing! thank you

    1. Marissa Stevens says:

      My pleasure, Cardi! So glad you enjoyed it.

      1. Marc Siegel says:

        I want to make this Boneless Leg of Lamb recipe for New Year’s Eve. Is it possible to cook part of it ahead? Please let me know your thoughts. I made this recipe for your baked lamb chops and they were just delicious! Please let me know if there’s a way to cook the leg ahead. Thanks!

        1. Marissa Stevens says:

          Hi Marc! I’m so glad you enjoyed the baked lamb chops! I’d love to say yes, but I have to say “no” – because you only cook the meat to medium-rare, it’s not a good idea from a food safety standpoint to partially cook it in advance. Here’s a link if you’d like to read more.