by Olena

Boneless Leg of Lamb Roast

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Olena Osipov
5 from 50 votes

How to cook perfect Boneless Leg of Lamb Roast every time. Herb crusted and garlic stuffed, this is easy roast lamb recipe anyone can make!

Roasts are easy and impressive! Try turkey breast roast, sirloin tip roast or even juicy Instant Pot turkey breast and never fret making a roast again!

boneless leg of lamb roast in a dutch oven

Boneless Leg of Lamb Recipe

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, just like roasted chicken breast. Cooking on high and uncovered are the keys to success!

I created this basic boneless leg of lamb recipe about 15 years ago. And I make it for Thanksgiving 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 Easter or a weekend dinner, you can do it!!!

Buying Best Lamb

Lamb is expensive. Like any red meat, like any meat. So I understand your fear of “screwing it up”. You will not. Boneless lamb is actually the easiest meat to roast. I just learnt how to make pot roast in Instant Pot. I still don’t know how to cook a prime rib.

When it comes to buying lamb I turn to Costco. 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.

boneless lamb roast, olive il, garlic, rosemary, salt and pepper

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.

Below are listed cooking times per pound.

  • Medium Rare: 130 – 135 degrees F internal temperature – about 16 minutes per pound.
  • Medium Well: 140 – 145 F internal temperature – about 18 minutes per pound.
  • Well-Done: 150 – 155 F internal temperature – about 20 minutes per pound.

It all comes down to checking often after a certain period of time. My best advice is:

  • For 4-5 lbs roast: Check after 1 hour for internal temperature with a meat thermometer and go from there.
  • For 2-3 lbs roast: Check after 45 minutes.

More Tips for Cooking Time:

  • Check often: The key is to check often towards the end with an internal meat thermometer.
  • All ovens vary: Age, electric vs. gas. Not to mention convection oven cooks food faster. So check earlier than later!
  • Meat will keep “cooking” as it rests: Please keep in mind internal temperature will rise while meat is resting after baking in the oven.
  • Bake uncovered: You need meat to brown on the outside, not steam.

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 medium well after resting.

steamy boneless lamb roast sliced on a cutting board

How to Cook Boneless Leg of Lamb

1. Season with Rosemary and Garlic

  • Prep: Preheat oven to 425 degrees F while you are preparing the roast. Cut garlic into thin slivers.
  • Make holes in the roast: In a medium roasting pan or Dutch oven, place deboned leg of lamb roast and make 15 inserts with a paring knife.
  • Stuff with garlic: Stick garlic slice into each opening until you run out of garlic.
  • Season with spices on both sides: 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 16 minutes per pound)
  • Medium Well: 135 F to 140 F (about 18 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

  • Important to let meat rest: Remove lamb roast from the oven and let rest uncovered for 15 minutes. Do not skip!
  • Remove casing: Transfer on a cutting board. Using a sharp carving knife, remove the casing. I highly recommend to sharpen the knife before slicing, helps a lot not to destroy the roast.
  • Carving roast: Slice into 1/4 inch slices against the grain. Thin slices of lamb taste better than thick ones.

how to cook boneless leg of lamb step by step

FAQs and More 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/one pot dinners and Instant Pot meals, 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.

Storing and Serving Suggestions

Storing leftovers: Refrigerate roast whole or sliced in an airtight container for up to 5 days. It tastes so good cold.

More Comfort Food Recipes

Boneless Leg of Lamb Roast

Boneless Leg of Lamb Roast {Easy Recipe!}

How to cook perfect Boneless Leg of Lamb Roast every time. Herb crusted and garlic stuffed, this is easy roast lamb recipe anyone can make!
4.95 from 50 votes
Print Save Rate
Course: Dinner
Cuisine: American Ukrainian
Prep Time: 10 minutes
Cook Time: 1 hour 30 minutes
Total Time: 1 hour 40 minutes
Servings: 10
Calories: 175kcal
Author: Olena Osipov

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. Remember meat will keep "cooking" as it rests.
    °Medium Rare: 130 - 135 degrees F internal temperature - about 16 minutes/lb.
    °Medium Well: 140 - 145 F internal temperature - about 18 minutes/lb.
    °Well-Done: 150 - 155 F internal temperature - about 20 minutes/lb.
  • My best advice for 4-5 lbs roast is 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 towards the end.
  • 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.
    Boneless Leg of Lamb Roast

Storing leftovers: Refrigerate roast whole or sliced in an airtight container for up to 5 days. It tastes so good cold.

    Video

    Notes

    • All ovens vary: Age, electric vs. gas. Not to mention convection oven cooks food faster. So check earlier than later!
    • Meat will keep "cooking" as it rests: Please keep in mind internal temperature will rise while meat is resting after baking in the oven.
    • Bake uncovered: You need meat to brown on the outside, not steam.
    • Do I have to marinate the lamb? No. Lamb is tender meat. You just need to season it properly.
    • Can I use boneless lamb shoulder? Yes. No changes.
    • Can I use fresh rosemary instead of dried? Yes.
    • 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: 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.
    • Make sure your knife is sharp: I highly recommend to sharpen carving knife right before slicing, to avoid "destroying" the roast.

    Nutrition

    Calories: 175kcal | Carbohydrates: 1g | Protein: 24g | Fat: 8g | Saturated Fat: 2g | Cholesterol: 73mg | Sodium: 362mg | Potassium: 343mg | Fiber: 1g | Sugar: 1g | Vitamin A: 21IU | Vitamin C: 1mg | Calcium: 18mg | Iron: 2mg
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    olena osipov in the studio

    Hello and welcome to iFOODreal.

    My name is Olena Osipov. I'm a mom to 2 boys, a wife to Alex and we reside on magical Vancouver Island in British Columbia, Canada. This is our healthy family recipes blog. Originally from Ukraine, I grew up on real food. As an adult, I struggled with diets for years because none worked long-term. Now for over 10 years, I cook easy healthy meals for my family. I can help you with “What’s for dinner?” too.

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