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When you think of a showstopping roast, what comes to mind? For me, it’s this Roasted Boneless Leg of Lamb. While beef, turkey, or ham are delicious, I like to liven things up with lamb because it tastes as wonderful as it looks! Cooking a leg of lamb may seem daunting, but it’s easier and faster than you might think. You can make a tender, juicy roast with just 15 minutes of prep and less than 2 hours of roasting time. This dish is perfect for Easter, spring holidays, celebratory family meals, or dinner parties year-round.
What sets this recipe apart is a savory herb infusion of olive oil, fresh garlic, Herbes de Provence, Dijon mustard, salt, and pepper. Instead of only rubbing the infusion on the outside, I unroll the roast, spread the mixture inside, then roll it back up. This extra step might seem unnecessary, but it’s worth it — you’ll be rewarded with a mouthwatering meal with minimal effort. Using boneless lamb makes it possible to season the inside; plus, it cooks faster, is easier to carve, and fits well in a roasting pan.
“I made this last night and it’s become an instant family favourite … when my fussiest eater says “you can make that again, Mum”, you know it’s a winner! I teamed it with a side salad (it was a 40 degree day here in Australia) and a red wine reduction which teamed beautifully.”
helen
Table of Contents
Roasted Boneless Leg of Lamb Ingredients
- Boneless Leg of Lamb: Look for a 5-6 pound roast (it will likely be wrapped in netting). It should have a pinkish-red color and be firm to the touch. A little marbling is good, but avoid excessive fat. Make sure it’s fresh or properly thawed if frozen.
- Olive Oil: I like to use cold-pressed extra virgin olive oil. It should have a vibrant greenish-yellow hue, meaning it’s fresh and flavorful.
- Dijon Mustard: Choose a Dijon mustard that’s creamy and has a good balance of tangy and spicy notes.
- Garlic: Look for garlic cloves that are plump and firm with smooth skin. They should feel dense and not hollow.
- Herbes de Provence: This dried herb blend is often used in French cuisine. It usually includes rosemary, thyme, oregano, marjoram and sometimes lavender. I try to find a blend that smells fresh and has a rich color.
- Fresh Rosemary (optional): Herbes de Provence includes dried rosemary, but you can add minced fresh rosemary to the herb rub for a more robust flavor.
- Kosher Salt: I prefer 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: For the best flavor, you can’t beat freshly ground black pepper! Look for peppercorns that are consistently sized and have a strong aroma
5 Recipe Tips
- Choosing Boneless vs. Bone-in: While both are delicious, boneless leg of lamb has some distinct advantages. It cooks faster, carves more easily, and fits better in standard roasting pans. You also get more meat for the weight, though it may cost more per pound than bone-in. The ability to season the inside of a boneless roast adds another layer of flavor.
- Prepping the Lamb: Begin by unrolling the leg of lamb and trimming away excess fat and tendon. This extra step ensures a more tender roast and better presentation.
- Herb Infusion: The magic happens when massaging the lamb inside and out with a fragrant mix of olive oil, fresh garlic, Herbes de Provence, and creamy Dijon mustard. This infuses deep flavor and moisture into the meat, making every bite delicious.
- Securing the Roast: After seasoning, carefully reroll the lamb and secure it with kitchen twine. This step is crucial – it helps maintain the roast’s shape and ensures even cooking. As it roasts, the lamb develops a succulent interior and a crisped, herbaceous crust, perfect for a show-stopping centerpiece.
- Avoid Overcooking: Use an instant-read thermometer to be sure you remove the meat from the oven at the proper time so it remains tender (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.
This Roasted Boneless Leg of Lamb is a delicious centerpiece for any special meal. It’s simpler to prepare than you might think, and the results are sure to impress. The herb-infused meat pairs beautifully with a variety of side dishes (lots of ideas below). Whether you’re serving it for a holiday feast or a weekend family dinner, don’t be surprised if this lamb roast becomes a requested favorite!
What to Serve Alongside
- Gratin Dauphinois (Creamy classic French potato gratin.)
- Lyonnaise Potatoes (Another delicious French potato side dish with caramelized onions that’s made on your stovetop.)
- Fondant Potatoes (These meltingly tender potatoes start on the stovetop and can finish in the oven while your lamb roast rests.)
- Mashed Red Potatoes (Ultra creamy with a method that might surprise you.)
- Brioche Dinner Rolls (Tender, buttery and so easy to make with this no-knead recipe.)
- Sugar Snap Pea Salad (The perfect pair to roast lamb if you’re making it in the springtime.)
- Strawberry Spinach Salad (With pecans, goat cheese, and a tangy, honey sweetened balsamic vinaigrette.)
- Strawberry Spinach Walnut Salad (A riff on the salad above with walnuts and a Strawberry Vinaigrette.)
- Caesar Salad (Because you can never go wrong with this classic salad.)
How to Make Roasted Boneless Leg of Lamb
Begin by preparing the roasting pan with a rack. Untie and unroll the lamb, trimming excess fat while leaving a thin layer on top. Mix the Dijon herb paste ingredients in a bowl until well combined. Spread some paste on the inside of the lamb, then roll and tie it with kitchen twine. Rub the remaining paste all over the outside.
Let the lamb sit at room temperature while preheating the oven to 425°F. Roast for 15 minutes, then reduce heat to 350°F and continue cooking until the internal temperature reaches 135°F for medium-rare. This typically takes 1 to 1 1/2 hours.
After roasting, let the lamb rest for 15-30 minutes before removing the twine and slicing. Remember, the temperature will rise slightly during resting. Slice thinly and arrange on a platter to serve. For added flavor, consider incorporating fresh rosemary or lemon zest into the herb paste.
Roasted Boneless Leg of Lamb
Video
Equipment
- Oven-Safe Baking Rack Ideal for perfectly roasted boneless leg of lamb!
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 (218 °C).
- Roast lamb in hot oven for 15 minutes. Reduce heat to 350 °F (177 °C) 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
- 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.
- 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
Nutrition information is automatically calculated, so should only be used as an approximation.
Need per pound time for cooking. Is it 15 or 20 minutes per pound?
Hi Jane! You’ll start the roast in a hot oven for 15 minutes, then reduce the temperature for the remainder for a total of 1 hour and 15 minutes to 1 1/2 hours for a 5 1/2 pound roast. I recommend checking the internal temperature with an instant read thermometer at the 1 hour mark at the lower temperature to make sure you don’t overcook the roast. I hope that helps!
Made this recipe for Easter, but forgot to save it. I have spent the last 2 weeks searching all the corners of the internet for it and I am so happy to have finally found it.
I’m so glad you found it, Bella! And I’m honored that you made and enjoyed it enough to seek it out!
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.
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.
This recipe is fantastic the lamb came out so tender & tasty. Bon Appetit
That’s wonderful to hear, Margerat! Thank you for letting me know.
Used this recipe last night and it was amazing! thank you
My pleasure, Cardi! So glad you enjoyed it.
I want to make this Boneless Leg of Lamb recipe for New Yearโs 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 thereโs a way to cook the leg ahead. Thanks!
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.
Fantastic. I’ve done this a few times for the family now and it’s a reliable favorite. Juicy and perfectly done each time. The paste and high starting temperature produce a lovely crust. The timings are about right but absolutely do use a meat thermometer, and start checking before time, to make sure you get it exactly to your liking. Mine were done a little sooner.
That’s wonderful to hear, DavidH! Thank you for your cooking notes.
The paste was absolutely delicious, except a bit too salty because I used the Morton Kosher salt. After 15 minutes of cooking, the house smelled wonderful. I am keeping your recipe and will pass it on to anyone who asks. ๐
I’m so glad you enjoyed it, Marguerite! Yes, it’s amazing how much saltier Morton kosher salt is compared to Diamond Crystal brand.
This was THE best recipe I’ve ever had for lamb, so tender and flavorful! Thank you, it’s a keeper!
My pleasure, Joanne! I’m so glad you enjoyed it. Thanks so much for coming back to let me know.
I made this last night and it’s become an instant family favourite … when my fussiest eater says “you can make that again, Mum”, you know it’s a winner! I teamed it with a side salad (it was a 40 degree day here in Australia) and a red wine reduction which teamed beautifully.
I love to hear this, Helen! I’m so happy to hear that this dish is a hit for you and your family!
Is one tablespoon of Kosher salt correct? It was way too salty for us and I ended up having to scrape the paste off the lamb after it was cooked and unfortunately it was still much to salty for our taste buds. Very easy to follow the recipe though, so thank you for that!
Hi Sofia! I use Diamond Crystal brand kosher salt and I’m wondering if you’re using Morton brand (it’s about twice as salty by volume). I should have noted the brand I use in the ingredient list and have added it now. As far as the quantity of salt, it’s actually well below what some reputable sources recommend (for example, America’s Test Kitchen recommends 1 teaspoon of kosher salt per pound of lamb roast), but it’s all about how it tastes to you, so I’m so sorry that the seasoning was off for you and your family.
Thank you for your reply. I did use Morton!! I had no idea that it differed that much?! Will try and look for another brand, or simply cut back on the amount next time. It was a great recipe so will definitely use it again. Thank you!
My pleasure, Sofia!