How to cook perfect Boneless Leg of Lamb Roast every time. Basic easy recipe anyone can make!
Boneless Leg of Lamb
You might not be aware yet. To roast boneless leg of lamb is my favourite way to celebrate anything. I love cooking deboned lamb because it’s so EASY but looks GRANDE on the table. Yes, it is super simple and hard to mess up.
I created this the best ever basic boneless roasted leg of lamb recipe about 15 years ago. And I make it for a special occasion. Or when I need to leave a lasting impression. Works every time.
Last time was my visiting mom that “doesn’t like” lamb. And a time before I made this roast to say “thank you” to the nicest plumber on Earth. Everyone loves it! And I will teach you how to cook the most perfect boneless leg of lamb in the oven. For Holidays, Easter dinner or a weekend dinner. You can do it!!!
Buying Best Lamb
Lamb is expensive. Like any red meat. Like any meat. So understand your fear of “screwing it up”. You will not. Boneless lamb is actually the easiest meat to roast. I still don’t know how to make a beef roast. Not to mention how to cook a prime rib.
When it comes to buying lamb I turn to Costco. I am not fancy enough or do not have time to go to a butcher shop. Frankly, I think those days are behind us. Plus I do not see a difference in meat unless it’s organic or locally raised etc.
Kirkland boneless leg of lamb from Costco does it for us. The cost is about $8 per pound. And 99% of lamb sold in Canada I ever saw is from Australia.
Bone In Vs. Boneless Leg of Lamb
I prefer and highly recommend to use boneless leg of lamb for many reasons:
- It is easy to fit into a roasting pan.
- It is easy to carve.
- You get more meat.
- And it probably cooks faster.
How Long to Cook Boneless Leg of Lamb?
How long do you cook a boneless leg of lamb? Cooking time depends on how you like your meat. Just like with steak.
It all comes down to checking often after a certain period of time. My best advice is:
- For 4-5 lbs roast check internal temperature with a meat thermometer after 1 hour and go from there.
- For 2-3 lbs roast, check after 45 minutes.
Below are listed cooking times per pound.
- Medium Rare: 120 F to 130 F internal temperature – about 14 minutes per pound
- Medium: 130 F to 140 F internal temperature – about 16 minutes per pound
- Well-Done: 140 F to 150 F internal temperature – about 18 minutes per pound
Remember meat will keep “cooking” as it rests.
More Tips for Cooking Time:
- The key is to check often with an internal meat thermometer.
- Please keep in mind internal temperature will rise while meat is resting after baking in the oven.
- All ovens vary: age, electric vs. gas. Not to mention convection oven cooks food faster.
- Bake uncovered.
What Temperature?
I know there is a slow roasted lamb cooking method at low 300 degrees F temperatures. My boneless lamb roast is baked at 425 degrees F. I think it yields juicy meat inside with browned outside within a reasonable amount of time.
Below is lamb cooked for 18 minutes/lb which ended up being well done after resting.
Boneless Lamb Roast FAQs and Tips
Do I have to marinate the lamb?
No. Lamb is tender meat. You just need to season it properly. My absolute favourite classic seasonings are garlic and rosemary. Maybe a squeeze of lemon at the end. So, no lamb marinade recipe to follow. Yay for simplicity.
Can I use boneless lamb shoulder?
Yes. I have done it many times. It depends what’s at the store when I’m there. SImple as that. I believe boneless lamb shoulder is even cheaper than the leg.
Can I use fresh rosemary instead of dried?
Yes. I use both fresh and dried rosemary with this recipe. One time I bought a bunch of fresh rosemary for making boneless turkey breast roast. It lasted a month in the fridge. Long enough for “the super nice plumber” dinner. But not long enough for “not liking lamb mom” dinner. So I have tried both many times.
What to do with all that fat?
Lamb is extremely fatty meat. You will see a lot of fat solidify at the bottom of the roasting pan pretty much immediately as it starts to cool off. And if you refrigerate leftovers, fat will solidify nicely into white chunks. I take this as an opportunity to discard extra fat and remove it before serving or reheating.
Plan ahead
Cooking boneless leg of lamb in the oven IS easy! It just needs enough cooking time. In our days of sheet pan dinners, one pot meals and Instant Pot I recommend to plan ahead with this recipe. Just make sure you understand your dinner will be on the table in 2 hours if you roast lamb.
I speak from my own experience. I was “caught off guard” a bit once last month.:) We ended up drinking a lot of wine and beer with a super nice plumber guy. It was a pleasure anyways.
How to Roast a Boneless Leg of Lamb
1. Season with Rosemary and Garlic
- In a medium roasting pan or Dutch oven, place deboned leg of lamb roast and make 15 inserts with a paring knife.
- Stick garlic slice into each opening until you run out of garlic.
- Rub roast with oil all around.
- Then sprinkle one side with half of rosemary, salt and pepper.
- Turn around and repeat on another side.
2. Bake Uncovered
Bake uncovered according until desired doneness.
- Medium Rare: 130 F to 135 F (about 12 minutes per pound)
- Medium: 135 F to 140 F (about 15 minutes per pound)
- Well-Done: 155 F to 165 F (about 20 minutes per pound)
My best advice is for 4-5 lbs roast to check internal temperature after 1 hour and go from there. For 2-3 lbs roast, check after 45 minutes. It all comes down to checking often after a certain period of time.
3. Let Rest and Carve
- Remove lamb roast from the oven and let rest uncovered for 15 minutes. Do not skip!
- Transfer on a cutting board.
- Using a sharp knife, remove the casing and slice into 1/4 inch slices against the grain. Thin slices of lamb taste better than thick ones. My husband is guilty here.
What to Serve with Leg of Lamb?
- Healthy mashed potatoes – so classic and satisfying.
- Cauliflower mashed potatoes – low carb alternative.
- Mashed sweet potatoes – sweet and savory at same time.
- Cucumber and tomato salad – cucumber and lamb are a match made in heaven.
- Grilled vegetables – if it’s grilling season wherever you are.
- Healthy spinach salad – can never go wrong with this simple salad.
Boneless Leg of Lamb Roast
How to cook perfect boneless leg of lamb roast every time. Basic EASY recipe anyone can make!
- Prep Time: 10 minutes
- Cook Time: 90 minutes
- Total Time: 1 hour 40 minutes
- Category: Dinner
- Method: Oven
- Cuisine: American Ukrainian
Ingredients
- 4–5 lbs boneless leg of lamb
- 5–7 large garlic cloves, cut into slivers
- 2 tbsp olive oil, extra virgin
- 2 tbsp rosemary, dried
- 1 1/4 tsp salt
- Ground black pepper, to taste
Instructions
- Preheat oven to 425 degrees F. In a medium roasting pan or Dutch oven, place boneless leg of lamb roast and make 15 inserts with a paring knife. Stick garlic slice into each opening until you run out of garlic.
- Rub roast with oil all around. Then sprinkle one side with half of rosemary, salt and pepper. Turn around and repeat on another side.
- Bake uncovered according until desired doneness. Medium Rare: 120 F to 130 F internal temperature – about 14 minutes per pound. Medium: 130 F to 140 F internal temperature – about 16 minutes per pound. Well-Done: 140 F to 150 F internal temperature – about 18 minutes per pound. Remember meat will keep “cooking” as it rests.
- My best advice is for 4-5 lbs roast to check internal temperature after 1 hour and go from there. For 2-3 lbs roast, check after 45 minutes. It all comes down to checking often after a certain period of time.
- Remove lamb roast from the oven and let rest uncovered for 15 minutes.
- Using a sharp knife, remove the casing and slice into 1/4 inch slices against the grain. Serve warm at a celebration table or use cold leftovers in sandwiches or salads.
Did you make this recipe? Please give it a star rating in the comments.
An important thing that is missing, it appears you cooked the leg while in the elastic netting, did this cause any issue. No where is it stated on the Costco package, or in recipes about that netting. Any discussion about tying the roast is done with kitchen cotton twine. You picture appears to indicate you cooked it with the netting.
Hi! You are right. I do cook my leg of lamb with the casing intact and cut it off afterwards. I have not had any issues with this.
I had a college friend named George Osipov in 1958. I believe he was from Russia. Any relation? He was a great guy, …excellent student, electronic engineering as I remember.
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Um no haha. WOuld be nice to have some nice and rich grandpa somewhere though. And a healthy one too. Osipov is quite common last name in Russia. Most Russians are smart. 🙂
I’m a novice with a meat thermometer, but I have one encased in silicone.
I’m not sure if I should insert the thermometer and then cook, checking the reading on the dial, or pierce the meat later, after one hour to chec it? Wouldn’t that release all the juiciness? Thanks to anyone who might have an answer for me 🙏
You check with thermometer after. Insert in the thickest part, wait till T stops rising and remove. Small poke won’t release all juices.
Thank you, I’ve never been sure!
Please check on the print button – sends the recipe to a page that doesn’t have a spot to print. I plan to make this tomorrow for Sunday dinner, it looks delicious. I am also Ukrainian, born in the U.S.
Nice to virtually meet you, Ruth. 🙂 It works on my Mac and iPhone. What device you are checking it on? Recipe opens in new page and then you use File-Print from your browser window. There shouldn’t be print button on that page. Enjoy!
I forgot what event or holiday I made this but it was very very good. Best way to cook boneless lamb leg. Had to find the recipe to make it again tonight! Thank you
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Thrilled you like this recipe Amelia!
Easy and tasty recipe!
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This was delicious! I did have to increase the roasting time, though. My 4.25 lb. roast took 90 minutes to reach 127 degrees. So flavorful!
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That’s great to hear Sandy!
This roast was really good. ve never had Lamb before, it was good. I served it with fresh green beans, yellow squash
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Hi Phyllis! Glad you enjoyed the lamb!
Love the different temps and times, Hubby and I like our lamb well done and this is perfect. We usually have chops but this is so easy and love the leftovers so will do it again.
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Glad to hear that the lamb recipe was enjoyed by both you and your husband Diana!
My husband loves lamb. But we don’t have it often. We had our 2.06 lb boneless leg of lamb roast for our Easter dinner. I love your recipe! It was so easy and very delicious! My husband is raving about it. I added oregano and savory along with the rosemary. Thank you.
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Gwen! I am so happy that you and your husband enjoyed the lamb:)
Tried this today on Easter Sunday and it was delicious! Thank you!
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You are so welcome Anne!
I baked a 3# boneless roast (in casing) for exactly 60 minutes at 350 degrees, after braising all sides on stovetop to seal juices. It was perfect.
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Fantastic to hear Jann!
This came out nice and juicy just as you said it would. I used fresh rosemary and thyme and used a whole head of garlic. I put it all in my small food processor and added the olive oil then slit the meat and stuffed it in and rubbed it all around – wow was it delicious!!
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Carla! Happy the roast turned out so delicious!
OMG!!!! Amazing. Thank you for this recipe. Followed exactly, and it was perfect!
You are so welcome Kevin!
Easier instructions could not be possible. I’m so very excited to try this tomorrow, Easter Sunday, April 12, 2020.
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Let me know how much you like it!
My comments are entered below, I just forgot to give this recipe 5 stars, which it totally deserves!
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I like the recipe and added a few modifications.
Overnight , I pat dry and season the lamb with Any combination of favorite salt : Himalayan , Mediterranean, or Sea salt as well as pepper: Peppercorn, Black, etc.
Layer chopped onion over all around lamb, seal and refrigerate.
Next day : Baste olive oil all over lamb.
Heat up skillet to medium high and sear all sides of lamb roast approximately 2 minutes per side.
Place in oven at 380 degrees.
Rotate pan every 30 minutes and check temp after 1 hour of oven time
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I had never cooked a leg of lamb, bone-in or boneless until I cooked this. I followed your recipe and placed my boneless 2.63 lb leg of lamb in a round, Pfaltzgraff(-like) crock (not sure of the brand) because that was the closest thing I had to a dutch oven. I covered the top of the meat with carrots and potatoes and I cooked it at 425 for 43 minutes. I removed it from the oven and the temperature was barely at 130 for medium but it still looked way too underdone for my taste so I moved the vegetables to a separate dish and cooked the lamb another 10 minutes, let it rest 10 min and then sliced it. It ended up being cooked to medium-well, barely pink.
I wondered if by adding the vegetables on top it interfered with the cooking time a bit but overall it was DELICIOUS! Very tasty and very tender! I will definitely be cooking this again. Thank you so much for sharing your wonderful, easy recipe.
Yum! My house smells so good and this is the first time I’ve made this. Thank you for sharing your family favorite!
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So happy to hear that you enjoyed this Debbie!
Thank you I’m trying it right now. I have the oven set at 360 but you’re recommending a much higher temperature so maybe I should turn the oven up, I don’t want to burn but I don’t want it rare either. I am looking for my meat thermometer oh dear!
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How did the leg of lamb turn out Kathy? Yes, I do recommend a higher temperature of 425F as I find it yields juicy meat inside with a nice browned outside. You just need to check the meat regularly with an internal meat thermometer!
Perfect…. Thank you for all the instructions…. I know it is simple but some people don”t know how to do it… All these instructions and videos have made me a really good cook..
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I’m so happy to read this! Thanks for your positive feedback, Patricia!
How long do you keep a boned leg of lamb covered whilst roasting?
I am not sure. Haven’t baked it in a while.
I love all you share with such care. You make every recipe so easy to follow. Thank you for all you share. My 4 1/2 boneless lamb roast came out wonderfully. I made it today for our 2020 New Year’s dinner. Every one ate until totally happy. My whole family asked for the recipe. Absolutely love your recipe. Thank you.
T.
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Awe, you are so welcome, Tanya! So happy to hear you are enjoying my recipes! Thanks so much for sharing my recipe with family and friends!
This is a good recipe to save since I didn’t have to buy ingredients I didn’t have on hand. The cooking time was perfect and we all enjoyed the meal. There was more slivered garlic left after I filled the inserts, so I made a few more slashes in the lamb and added more garlic.
The cooking time was perfect and the lamb was pink in the center after 90 minutes at 425 degrees. Next time I’ll remember to roast some veggies along with the lamb.
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So happy to hear, Elaine. Merry Christmas!
The timing and internal heat suggestions were so helpful! I’ve never made lamb before and this recipe made it very easy and turned out great! Thank you!
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You are very welcome, Laura!:) Happy Holidays!
Wonderful way to cook lamb: great taste and so easy. Thank you.
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That is so amazing to hear! Glad you enjoyed my recipe, Janet.
I plan on trying your recipe on Christmas. I hope to use the rotisserie on my power air fryer (if the lamb is no to big). I know the cooking times and oven temperature will be different
Good luck! Please let me know how it turns out. I am yet to try an air fryer. 🙂
What kind of roasting pan do you use? Stainless steel? Aluminum? Non-stick?
Also, do you use a rack in the pan so the fat drips off?
Just this 6 quart Lodge dutch oven. No rack.
Thank you!!
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Bought a 5 pound Costco boneless roast and followed the directions exactly. Surprisingly, came out a little tough. I think perhaps my husband cut the slices a little too thick, so that may be why. I will try making it again for Easter.
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Hm… Could be many reasons. Here is what I found https://www.chowhound.com/post/tough-lamb-973363?page=2 I know sometimes same Costco lamb cut is more tough than others can be. I wonder if it is mostly specific batch fault. Hopefully next time. 🙂
Making this tonight…..ideas for leftovers would be appreciated…..happy holidays!
You think there will be leftovers, Gayle? 🙂 I usually love cold sliced lamb in a salad like arugula salad.
Leftover lamb sandwich on rustic bread with olive tapenade. So good☺️
Oh my gosh. How come we are not neighbours?! Doesn’t mean we would see each other all winter but still more chances for your deliciousness. 🙂
I recommend finding an Irish Lamb Stew on the internet. If you have leftover roasted new potatoes and/or carrots, you can add them. Also, I find that the Lamb Stew only gets better after the next day and the extra freezes well. After freezing, sometimes the potatoes break up, but that only thickens the gravy.
Great suggestions, Sue.
very good
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Yay!!!
Awesome! The garlic and rosemary does it!!
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Always rosemary and garlic with lamb!:)
Hi, I was just reading your recipe and wondering if you’ve ever tried this exact recipe but in a slow cooker. I usually make my lamb shanks in a slow cooker and come home with a wonderful aroma for supper. Do you think it can be done with a boneless leg of lamb?
Yes I think so. It just won’t be exactly roasted. But you probably know that.:)
Quicker and easier way I use for a boneless leg of lamb. Remove lamb from string pouch first and open it out flat.
Kosher salt and pepper on both sides. Combine oil, crushed garlic, rosemary, grated lemon rind and rub generously on the non-fat side. Bake at 450 F for about 20 minutes or desired doneness. This also works great on a gas grill. Just treat it like a very thick steak.
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Sounds fantastic! Thanks so much for sharing!
I am making this for dinner tonight can’t wait to try it!
I cooked this recipe tonight for my wife, in our 5th wheel’s little oven and it was delicious!!! I am a disabled Marine and it wasn’t difficult to cook at all… It might have taken me a little longer to prep but I have nothing but time on my side these days…
Semper Fi
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Good for you, Jerry! Lamb is easier than many people think. The lewy is to stop cooking it at the right time. And you must have a kick ass 5th wheel.:) Usually RV ovens are quite slow…
I love lamb. Lived in Turkey for 2 years(military dependant) Lamb is the meat of choice. Getting ready to try your recipe. Thank you.
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I just made this for Easter dinner. It came out perfectly!!! Thank you!!
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Sorry but I don’t understand the temperature. Preheat 425f but cook at 130 F. How does that work.
130 F is an internal temperature of meat to check with meat thermometer for desired doneness when it’s cooked. Sorry I just saw this comment. Hope not too late but sorry if it is.
I made this recipe for Christmas Day. It turned out beautiful! Not only that, it was simple to make and left me more time with my family! Thank you Olena for this recipe!
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🙂 You are very welcome! Happy New Year! Xoxo