by Olena

Boneless Leg of Lamb Roast

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Olena Osipov
5 from 51 votes

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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 boneless 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 dinner or a weekend dinner, you can do it!!!

Why This Recipe Works?

  • Easy to make: Boneless lamb is actually the easiest red meat to roast. Lamb is expensive, so I understand your fear of “screwing it up”. You will not.
  • 6 Ingredients: You more likely have on hand right now.
  • Tender juicy meat: Thanks to the precise cook times for your preferred level of doneness.
  • Garlic lovers dream: Stuffed with over 30 slivers of fresh garlic.
  • Foolproof recipe: This recipe is 15 years old tried and tested on our family.
  • Video: If you are more of a visual learner, video instructions will be helpful.
sliced boneless leg of lamb roast

Ingredients for Roast Lamb Recipe

  • Boneless leg of lamb: 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.

How much boneless leg of lamb per person? General rule of thumb is 1/2 lb per person.

  • Garlic: Juicy, fresh and plump garlic cloves make all the difference. After all, it’s a garlic lover’s dream lamb recipe! No garlic powder please.
  • Dried rosemary: Dried rosemary is more convenient. However, you can use fresh rosemary if you wish and it will yield even more flavor. Or a mixture of both. Fresh herbs are always a good idea!
  • Olive oil: Extra virgin olive oil goes well with lamb naturally. But you can also use avocado oil or grapeseed oil.
  • Salt and black pepper: To season and taste.
lamb, oil, garlic, rosemary, salt and pepper

What Is Boneless Leg of Lamb?

Boneless leg of lamb roast is a leg of lamb where bone has been removed, and meat rolled, tied or netted into a shape of oval roast. It is very easy to roast!

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 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 (no need for a rack but you can), place deboned leg of lamb roast and make about 20-30 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.

Fat side up or down? Like with any roast, the best practice is to cook meat with fat side up so it keeps it moist and juices locked in inside. It acts like a blanket.

2. Bake Uncovered

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 according the schedule below until desired doneness. Cooking times are listed per 1 lb.

  • 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.

All ovens vary: Age, electric vs. gas etc. Not to mention convection oven cooks food faster. So check earlier than later! 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.

4. Roast Potatoes in Fat Drippings (Optional but Good)

Lamb is extremely fatty meat. You will see a lot of fat and drippings at the bottom of roasting pan. Take advantage of it to make boneless leg of lamb and potatoes (and other veggies), so good!

  • Remove some fat and drippings: Scoop out 1 cup as it is just too much and roasted vegetables will come out too greasy. Not healthy and there is enough flavor in remaining juice and fat.

Do not drain fat in your sink to avoid clogged pipes. Instead, let it solidify for a few hours in a cup before discarding.

  • Add veggies and seasonings: I added about 2 lbs potatoes, 2 carrots, raw stems from making mushroom appetizers, 1/2 tbsp garlic powder, 3/4 tsp salt and pepper to taste. Then stir to coat.
  • Bake: At same 450 degrees F for about 35 minutes or until fork tender. You can prep the veggies and seasonings while lamb is cooking, so after just pop them in without even turning off the oven.

More Tips for Foolproof Roast Lamb

  • 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.
  • Don’t remove the casing before cooking: Under any circumstances keep netting or rope on. It is what is holding pieces of meat together. If you remove it, meat will fall apart.
  • Bake roast uncovered: You need meat to brown on the outside, not steam. If you cover it with a lid or aluminum foil, meat will steam instead of roasting.
  • Adjust for your oven: All ovens vary, I can’t stress this enough! If your oven runs hotter or takes longer to cook, adjust cook time accordingly to avoid overcooked or undercooked lamb. Rule of thumb is to start checking with internal meat thermometer 1/2 hour before end of cook time as per recipe.

Common Lamb Roast FAQs

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.

How do I get browned crispy skin?

You can try broiling for a few minutes at the end. Lamb is quite fatty, so drying it out is harder than lean poultry.

How to cook boneless leg of lamb in convection oven?

Convection ovens cook food faster than regular (simple) ovens. To cook any recipe in a convection oven, follow this easy formula: reduce the temperature by 25 degrees F or reduce the cook time by 25%. Today some ovens even offer convection conversion completely eliminating any guesswork!

Where to buy boneless leg of lamb?

I usually buy mine at Costco. Most large supermarkets carry it.

Can you slow cook boneless leg of lamb?

Yes, feel free to give this Greek slow cooker leg of lamb recipe a try.

Can you cook a boneless leg of lamb in an air fryer?

Yes but it has to be butterflied first and a smaller piece, about 1 lb. Check out this recipe.

Boneless leg of lamb in sous vide?

Yes! This lamb sous vide recipe looks so good!

Serving Suggestions

Serve sliced lamb on its own, or drizzled with freshly squeezed lemon juice and/or fresh mint jelly. We usually have lemon on hand at all times, so it rounds up meat flavors nicely.

Making This Recipe in Advance

Make ahead: To save time during a busy day of cooking of a holiday, you can stuff and season roast, cover and refrigerate for 24 hours. Then let it come to room temperature and roast as per recipe.

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

Freeze: Freeze leftovers sliced or cut into bite sized pieces in an airtight container for up to 3 months. Thaw in refrigerator and then use leftovers for as a protein in a salad for lunch, sandwich on-the-go or for lamb tacos!

More Comfort Food Recipes

sliced stuffed with garlic leg of lamb
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 anyone can make!
4.95 from 51 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: 8
Calories: 175kcal
Author: Olena Osipov

Ingredients

Boneless Leg of Lamb Roast

  • 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

Roasted Potatoes After (Optional)

  • 2 lbs potatoes cubed
  • 2 large carrots sliced
  • 1/2 tbsp garlic powder
  • 3/4 tsp salt
  • Groudn black pepper

Instructions

  • Preheat oven to 425 degrees F.
    Boneless Leg of Lamb Roast
  • In a medium roasting pan or Dutch oven, place boneless leg of lamb roast and make 20-30 inserts with a paring knife. Stick garlic slice into each opening until you run out of garlic.
    Boneless Leg of Lamb Roast
  • Rub roast with oil all around. Then sprinkle one side with half of rosemary, salt and pepper. Turn around and repeat on another side.
    Boneless Leg of Lamb Roast
  • 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.
    Boneless Leg of Lamb Roast
  • 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.
    Boneless Leg of Lamb Roast
  • Remove lamb roast from the oven and let rest uncovered for 15 minutes.
    Boneless Leg of Lamb Roast
  • Using  a sharp knife, remove the casing and discard it.
    Boneless Leg of Lamb Roast
  • Slice lamb 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

Roast Potatoes in Fat Drippings (Optional)

  • Scoop out 1 cup of fat and drippings from the pan and leave in the rest.
    Boneless Leg of Lamb Roast
  • Add potatoes, carrots, garlic powder, salt and pepper and stir well.
    Boneless Leg of Lamb Roast
  • Bake at 450 degrees F for about 35 minutes or until fork tender. You can prep the veggies and seasonings while lamb is cooking, so after just pop them in without even turning off the oven.
    Boneless Leg of Lamb Roast

Make ahead: To save time during a busy day of cooking of a holiday, you can stuff and season roast, cover and refrigerate for 24 hours. Then let it come to room temperature and roast as per recipe.

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

      Freeze: Freeze leftovers sliced or cut into bite sized pieces in an airtight container for up to 3 months. Thaw in refrigerator and then use leftovers for as a protein in a salad for lunch, sandwich on-the-go or for lamb tacos!

        Video

        Notes

        • Don’t remove the casing before cooking: Under any circumstances keep netting or rope on. It is what is holding pieces of meat together. If you remove it, meat will fall apart.
        • Bake roast uncovered: You need meat to brown on the outside, not steam. If you cover it with a lid or aluminum foil, meat will steam instead of roasting.
        • Adjust for your oven: All ovens vary, I can’t stress this enough! If your oven runs hotter or takes longer to cook, adjust cook time accordingly to avoid overcooked or undercooked lamb. Rule of thumb is to start checking with internal meat thermometer 1/2 hour before end of cook time as per recipe.
        • Meat will keep “cooking” as it rests: Please keep in mind internal temperature will rise while meat is resting after baking in the oven.
        • 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.
        • 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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