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A stunning centerpiece for any meal, my Roasted Boneless Leg of Lamb is a recipe you can count on. With just 15 minutes of prep and a handful of everyday ingredients, my no-fail method relies on one simple technique: seasoning both the inside and the outside of the roast. And that means a succulent, deeply flavorful roast every single time.
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.
This extra step might seem unnecessary, but I promise you, it’s worth it. It’s the secret to a mouthwatering meal with minimal effort. Using boneless lamb makes this possible; 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
Why This Recipe Works
- Seasoning the Roast Both Inside and Out. Most recipes have you rub the outside of the netted roast. Here you’ll take a few extra minutes to untie and unroll it, to rub the garlic-Dijon-herb paste deep into the meat. This seasons the whole roast, not just the crust.
- High-Heat Sets the Crust. Starting the lamb at 425°F creates a gorgeous, herbaceous crust. Once the crust is set, you’ll drop the heat to 350°F so the inside cooks gently and evenly.
- More than a Rub. The combination of Dijon mustard, garlic, and Herbes de Provence isn’t a typical rub; it’s a flavor infusion and helps keep the meat moist all the way through.
- Easy Carving. By using a boneless roast and tying it, you end up with a uniform, even shape. It cooks more evenly and makes carving at the table simpler. No awkward bone to cut around.
Roasted Boneless Leg of Lamb Ingredients
- Boneless Leg of Lamb: Look for a 5-6 pound roast. It will likely come rolled in netting that you’ll remove to season the inside.
- Dijon Mustard: Choose a quality brand that’s you’d happily slather on a sandwich.
- Garlic: Use fresh, plump, firm garlic cloves.
- Herbes de Provence: A mix of dried herbs that varies, usually: rosemary, thyme, oregano, marjoram and sometimes lavender.
- Olive Oil: Use a good quality extra-virgin olive oil.
- Kosher Salt: I use Diamond Crystal brand. If you use Morton, please be aware it’s almost twice as salty, so you’ll need to halve the amount.
- Freshly Ground Black Pepper
How to Make Roasted Boneless Leg of Lamb
Prep Lamb; Make Herb Paste to Rub Inside and Out: If the roast is wrapped in netting, snip and remove it; then unroll. Trim hard or excess fat, leaving a thin layer on the outside. Mix the Dijon herb paste ingredients together in a bowl until emulsified. Spread some of the herb paste on the inside of the lamb, then roll and tie roast with kitchen twine. Rub the remaining paste all over the outside.Begin by preparing the roasting pan with a rack.
Roast in Two Stages: 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.)
Rest, Snip, and Slice: 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 roast and arrange on a platter to serve.
My Pro Tips for a Perfect Roast
- The Secret to a Perfect Medium-Rare: Use an instant-read thermometer to avoid the disappointment of overcooking. Pull the roast from the oven at 135°F, maximum.
- Trust in Carryover Cooking: Once you remove the roast from the oven, the internal temperature will continue to rise by 5-10 degrees. Your 135°F roast will become a perfect 140-145°F (medium-rare) as it rests.
- Don’t Skip the Rest: Letting the lamb rest for 15-30 minutes allows the juices to redistribute throughout the meat. If you slice it immediately, the juices will flow out onto your cutting board instead of staying in the roast.
- How to Tie the Roast: Don’t be intimidated by the kitchen twine. You don’t need a fancy butcher’s knot. Just roll the lamb back up into its original shape and tie it snugly in three places: one in the center and one at each end.
Simple Variations
- For Brighter Flavor: Add 1 teaspoon of fresh lemon zest to the herb paste.
- For a Rosemary-Forward Roast: Herbes de Provence already has rosemary, but if you’re a big fan (like I am), swap half of it for 1 tablespoon of finely minced fresh rosemary.
Your Questions, Answered (FAQ)
Yes. For this recipe, you must remove the netting. Removing it allows you to unroll the lamb and spread that incredible Dijon-herb paste inside the roast, which is the key to making every bite flavorful. Then you’ll re-tie it with kitchen twine.
I use a two-stage method: a 15-minute blast at 425°F to build a crust, followed by a long, steady roast at 350°F to cook it gently and evenly.
Your thermometer should read 135°F when you pull it from the oven. It will rise to a perfect 140-145°F (medium-rare) as it rests.
No. Do not cover it. Covering it with foil would steam the meat and prevent that delicious, crispy herb crust from forming.
My Key Temperatures for Lamb
Use this as your guide. Always pull the meat from the oven 5-10 degrees before your target temperature.
- 130-135°F (Pull Temp): Medium-Rare (My #1 recommendation)
- 140-145°F (Pull Temp): Medium
- 150°F+ (Pull Temp): Medium-Well (I advise against this, as the lamb will be less tender.)
What to Serve Alongside
This roasted boneless leg of lamb is a delicious centerpiece for any special meal. The herb-infused meat pairs beautifully with a variety of side dishes.
- 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.)
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
- Prep Pan and Lamb: 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.
- Make the Herb Paste: Whisk together all Dijon Herb Paste ingredients in a medium bowl until they emulsify into a uniform paste.
- Season Inside and Out: 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: Preheat oven to 425 °F (218 °C).
- Roast High: Roast lamb in hot oven for 15 minutes. Transfer roast to cutting board; let stand 15-30 minutes before slicing.
- Roast Low: Reduce heat to 350 °F °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.
- Rest and Slice: Transfer the roast to a cutting board; let stand 15-30 minutes before slicing. Snip the twine with kitchen shears; remove and discard. Slice the roast thinly (about 1/4-inch) and arrange on a platter. Serve.
Notes
- Salt: I develop all my recipes with Diamond Crystal brand kosher salt. If you are using Morton’s, which is much saltier, I recommend cutting the salt in the paste to 2 teaspoons.
- My Favorite Tweaks: I personally love adding 1 teaspoon of fresh lemon zest to the paste for a bit of brightness. If you’re a big rosemary fan, feel free to use 1 tablespoon of Herbes de Provence and 1 tablespoon of minced fresh rosemary instead of the 2 tablespoons of dried.
- The Temperature is Key: Please, trust me on this—use an instant read thermometer! Pull the roast at 135°F for a perfect medium-rare. It will look underdone, but the temperature will rise to a perfect 140-145°F as it rests. This is the single most important step for a juicy, tender roast.
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!