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Amazing Roasted Boneless Leg of Lamb with Creamy Horseradish Dipping Sauce

The perfect main dish for Easter, Christmas, or any Holiday meal this Roasted Boneless Leg of Lamb is easy to prepare and a total show stopper! With minimal prep work, a simple garlic mixture for coating, and a two ingredient dipping sauce this is a great and impressive dish to make for friends and family!

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Overhead view of a roasted boneless leg of lamb on a platter, half of it sliced open revealing a tender pink inside.

Boneless Lamb Roast Recipe

A leg of lamb is a great option for a holiday meal. For many years a leg of lamb has always been our family’s go-to meal for Christmas dinner.

For a long time I would always buy the leg of lamb with the bone still attached and then I discovered how much better the boneless leg of lamb was when I couldn’t find a bone-in version.

They are the same cut of meat yes but I found once the bone was removed the roast got a much more even cook. Not only that but it also easier to cut and serve as well.

Through the years I also found that what a lot of lamb roast recipes are missing is a dipping sauce. Especially for those who are trying it for the first time, the dipping sauce helps the tasting of a new food be way less intimidating. So I developed a creamy horseradish sauce that is super simple, like 2 ingredients and some water simple that helps elevate this meal to the next level.

Now the first time cooking lamb can be super intimidating. So I will try to go through as much detail as I can in the post as well as leave as many tips and answer questions as I can.

I mean I get it you are spending $35-45 on this roast, I don’t want you to mess it up!

So let’s start with what you need.

Close up of slices of roasted leg od lamb show off tender and pink roast.

Ingredients

  • Boneless Leg of Lamb – Most stores you are going to find the size to be from 2.5 to 3.5 pounds. Now if you are buying a leg of lamb not during a holiday like Christmas or Easter they might be hard to find. I have had luck at specialty stores, like a local butcher grocery where I live and the nationally known Whole Foods. At my local butcher the size of the boneless leg of lamb is consistently about 2.5 pounds. Talking to the butcher at Whole Foods he told me that all of there boneless leg of lambs average out at about 3.5 pounds. Any size you can find will work. I will also note that especially if it isn’t during the holidays the leg of lamb might not be on display. When I was at Whole Foods I had to ask because they didn’t have it in the display case but the butcher had some available in the back and got it out for me.
  • Garlic – To help with the flavorful topping! I call for about 6 garlic cloves here and it yields a good amount of garlic but with out being too much.
  • Olive Oil – For this recipe since it is a nice roast that depends on just a few nice ingredients I recommend using a nicer Olive Oil. A lot of cheap olive oils on the shelves at the grocery can be rancid, so try to use one that has a good taste when you try it raw on it’s own. My personal go-to is California Olive Ranch 100% California Grown, not an ad just a huge fan.
  • Dijon Mustard – A little Dijon Mustard to help with the flavor and creaminess of the topping for the lamb.
  • Kosher Salt – I recommend only using kosher salt for this recipe, kosher salt varies from table salt in the way the flakiness and salt crystals are formed, so the way that kosher salt dissolves into the dish is going to be different from how table salt would work. In a pinch you can use sea salt. My favorite kosher salt is Diamond Crystal Kosher Salt.
  • Fresh Rosemary & Thyme – I find the combo of these to herbs to be a delicious power couple of flavor. They bring the right herb taste to the roast lamb without being overpowering.
  • Sour Cream – For the dipping sauce. This is the base that the horseradish will be added to.
  • Prepared Horseradish – A few scoops of prepared horseradish into the sour cream is essentially all the dip is, some water will be added to thin it out. I will note that amount I use is fairly light, I used just enough for some flavor and that my kids still enjoyed it. If you and the people you are serving it too are big fans of horseradish go ahead and add a little more tea your liking.

Note: Kitchen twine is needed for this dish.

For a complete detailed list of the ingredients continue towards the bottom of the page.

Ingredients for boneless leg of lamb roast laid out on a tabletop.

Instructions for Cooking Boneless Leg of Lamb

Preheat your oven to 350º F. Line a sheet pan or roasting pan with aluminum foil.

Prepare the topping for the lamb by adding the garlic, olive oil, dijon mustard, kosher salt, rosemary, and thyme to a single serve blender.

NOTE: If you don’t have a single serve blender you can attempt to make in in a full size blender or food processor but since the amount going into the blender isn’t every much you might have trouble… you could double the amount of the garlic sauce in order to blend it smooth and just not use all that extra sauce. Or you can also just mix everything by hand, albeit it might take a bit longer and not be quiet as smooth, if you are proceeding this way just ensure that the garlic is finely minced as well as the herbs, in a bowl whisk everything together to get a nice sauce.

If you are using the single serve blender pulse together until the garlic mixture becomes smooth, since it is a thick mixture you might have to scrap down the sides often and keep pulsing the blender until it is a thick yet mostly smooth sauce.

Collage before and after the garlic mixture for topping the lamb leg in a single serve blender cup.

Carefully remove the netting from the lamb while keeping the roast together in the shape it came in as much as possible. I chose to remove the netting for this recipe because I think it gets in the way of having a nice outside crust on the roasted boneless leg of lamb. The netting is there to keep the roast together where the butcher took out the leg bone. Further down you will see a photo with dashed lines where you are going to re-tie the lamb leg together gently with kitchen twine after spreading the garlic mixture on to the lamb.

Lay the lamb roast fat side up. Gently dry with a paper towel if needed.

With a sharp knife make diagnal scores in the fat about 1 inch apart in one direction and then matching perpendicular lines in the other direction, creating a grid pattern. Scoop the garlic mixture overtop the lamb and spread all over the top and sides, ensuring to get in the scores of the fat as well. 

Collage showing a boneless leg of lamb and the leg of lamb scored with cuts in the fat layer.
A lamb roasted covered in a garlic mixture and with dotted lines showing where to tie kitchen twine to keep the lamb together.

Now carefully with kitchen twine as to not wipe off the garlic mixture grab a long length of kitchen twine and bring it underneath the long way and around the top of the lamb, tie together gently. Now on the short side take two lengths of kitchen twine and carefully go under and over the lamb roast about 1/3 of the way from the ends gently tying together. Paying extra attention on the short sides that you are keeping the open cut from the bone closed if possible. Tying the lamb this way with the twine will keep the lamb in a roast shape instead of ballooning out where the bone had once been without needing the netting.

Transfer to the oven. Cook 30 minutes for every pound.

How Long Do You Cook Boneless Lamb For?

Boneless Leg of Lamb Roasting Times per PoundMinutes
2 lbs60
2.5 lbs75
3 lbs90
3.5 lbs105
*times will vary, for best results start checking temperature before given cooking length time to best judge doneness

At What Temperature is Boneless Leg of Lamb Done?

Use a meat thermometor to check the doneness.

Leg of Lamb DonenessTemperature
Medium/Rare145º F
Medium150º-155ºF
Well160º F

145º F will be medium-rare, 150º to 155º F will be medium, and 160º F will be well done.

Let the lamb rest for at least 10 minutes, gently cut off the twine before slicing to serve. Serve with the Horseradish Cream sauce below.

Close up of a slice of boneless leg of lamb with a pink center and crispy looking top.

How to make Horseradish Cream:

Add sour cream, horseradish, and water to a small bowl. Stir to combine, taste adjust as needed. Cover and refrigerate until ready to use.

Collage showing the ingredients for the creamy horseradish dipping sauce and the sauce mixed together in a bowl.

Tips, Tricks, and Questions?

What is the best temperature to cook a leg of lamb?

350º F

How do you make lamb tender?

I suggest cooking to 150º F. An over cooked lamb tends to get tough and undercooked tends to be chewy. After years of cooking a leg of lamb I have found that aiming to take it out of the oven at 150º F yields the best results.

Can I leave the netting on? I don’t have any kitchen twine.

Absolutely you can leave in on and not use kitchen twine. Just keep in mind though as you take the netting off before serving most if not all the flavorful garlic mixture will come off with it, the lamb will still be delicious though!

Have Leftovers?

Try my Leftover Lamb Curry!

A boneless leg of lamb roasted to perfection on a large platter, half of it cut open into slices showing off a tender pink inside.

If you are making this Roasted Boneless Leg of Lamb you might like these side dishes to go with it:

Overhead close up of a half sliced up roasted leg of lamb show tender pink meat.

Roasted Boneless Leg of Lamb

Yield: Serves 6
Prep Time: 15 minutes
Cook Time: 1 hour 45 minutes
Total Time: 2 hours

Perfect for Easter, Christmas, or any holiday meal, this show stopping Boneless Leg of Lamb is actually pretty simple to make! With minimal prep, easy seasonings, and a two-ingredient dipping sauce this is a great main dish to share with friends and family!

Ingredients

  • 2.5-3.5 pound boneless leg of lamb
  • 6 cloves garlic, peeled
  • 3 tablespoons olive oil
  • 1 tablespoon dijon mustard
  • 2 teaspoons kosher salt
  • 1 tablespoon fresh rosemary, chopped
  • 1 tablespoon fresh thyme, chopped

For Horseradish Cream:

  • 1/2 cup sour cream
  • 2 teaspoons prepared horseradish
  • 2 teaspoons water

Instructions

  1. Preheat your oven to 350º F. Line a sheet pan or roasting pan with aluminum foil.
  2. Prepare the topping for the lamb by adding the garlic, olive oil, dijon mustard, kosher salt, rosemary, & thyme to a single serve blender. Pulse together until the mixture becomes smooth, since it is a thick mixture you might have to scrap down the sides often and keep pulsing the blender until it is sauce like.
  3. Carefully remove the netting from the lamb while keeping the roast together in the shape it came in as much as possible. Lay the lamb roast fat side up. Gently dry with a paper towel if needed.
  4. With a sharp knife make diagnal scores in the fat about 1 inch apart in one direction and then matching perpendicular lines in the other direction, creating a grid pattern. Scoop the garlic mixture overtop the lamb and spread all over the top and sides, ensuring to get in the scores of the fat as well.
  5. Now carefully with kitchen twine as to not wipe off the garlic mixture grab a long length of kitchen twine and bring it underneath the long way and around the top of the lamb, tie together gently. Now on the short side take two lengths of kitchen twine and carefully go under and over the lamb roast about 1/3 of the way from the ends gently tying together. Paying extra attention on the short sides that you are keeping the open cut from the bone closed if possible. Tying the lamb this way with the twine will keep the lamb in a roast shape instead of ballooning out where the bone had once been without needing the netting.
  6. Transfer to the oven. Cook 30 minutes for every pound. Use a meat thermometor to check the doneness. 145º F will be medium-rare, 150º to 155º F will be medium, and 160º F will be well done. Let the lamb rest for at least 10 minutes before removing twine and slicing to serve. Serve with the Horseradish Cream sauce below.

Horseradish Cream:

  1. Add sour cream, horseradish, and water to a small bowl. Stir to combine, taste adjust as needed. Cover and refrigerate until ready to use.

Notes

A boneless leg of lamb with serve about 6 to 8 people, I always think it is a good idea to serve small portions since this can be a very rich meat.

Recommended Products

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Nutrition Information:
Yield: 6 Serving Size: 1
Amount Per Serving: Calories: 1276Total Fat: 85gSaturated Fat: 34gTrans Fat: 0gUnsaturated Fat: 44gCholesterol: 433mgSodium: 800mgCarbohydrates: 2gFiber: 0gSugar: 1gProtein: 117g

Nutritional data is automated, final nutritional information will depend on ingredients used and any changes made.

Did you make this recipe?

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Peace & Love

Lauren, The Schmidty Wife

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