This post may contain affiliate links. Please read our privacy policy.

This festive boneless leg of lamb is seasoned with garlic, orange zest, and herbs and marinated overnight for a deep flavor. Then, the lamb is covered in a thick layer of mustardy panko breadcrumbs speckled with fresh parsley, which forms a fabulous crust. The crust falls apart a bit as you slice the roast, but just scoop up the crumbles that fall to the side and serve them up with the slices of tender, pink lamb. The bits and pieces that stick in the pan? Those are yours for snacking.

It is quite a showstopper on the table, a perfect holiday entree, and the layers of flavor and texture always have everyone coming back for seconds. Think about serving it with a simple Herb Orzo Salad, lemony roasted Brussels sprouts, and a beautiful salad like this Winter Salad.

Table of Contents

Herbed Boneless Leg of Lamb with Mustard Crust in a baking dish.

Herbed Boneless Leg of Lamb with Mustard Crust: Deeply flavored with a wonderful crunchy topping, this is a showstopper of a main course for any holiday.

Tweet This

Herbed Boneless Leg of Lamb Ingredients

For the Herbed Boneless Leg of Lamb recipe, you’ll need just a handful of ingredients:

For the Lamb

  • Boneless leg of lamb – Roll up the boneless leg of lamb and tie it with twine before using. You can also ask your butcher to do this for you.
  • Garlic – It’s okay to leave the cloves whole here because they get blended up in the recipe.
  • Orange zest – Adds a little fresh citrusy flavor to the lamb.
  • Thyme – It’s best to use fresh thyme leaves.
  • Rosemary – I love the fragrant, woodsy flavor that rosemary adds. It goes so well with the mustard crust.
  • Olive oil – Helps make the spice rub spreadable so you can get it in every nook and cranny of the rolled lamb.

For the Mustard Crust

  • Dijon mustard – You can use coarse or smooth mustard. You can even branch out and use a mix of mustards, like half whole-grain and half Dijon. I like Dijon for its distinctive, winey, potent flavor.
  • Olive oil – Helps the topping get browned and crunchy in the oven.
  • Panko – These super crunchy yet light breadcrumbs are perfect for absorbing flavor and adding texture to this dish.
  • Flat-leaf parsley – Adds flavor and color to this crunchy topping!
Herbed Boneless Leg of Lamb with Mustard Crust being sliced on a cutting board.

How to Make Herbed Boneless Leg of Lamb with Mustard Crust

  1. Season the lamb: Throw the garlic, orange zest, thyme, and rosemary into the food processor. Blend them with the olive oil into a smooth paste, then rub that all over the lamb. Refrigerate overnight.
  2. Make the topping: With the oven preheating and the lamb sitting out, put the topping ingredients into a bowl. Blend them together and then press them onto the top of the lamb.
  3. Roast: Roast at a high temperature for 15 minutes and then turn it down and roast for another hour. Rest for 20 minutes before slicing and serving warm.
Partially-sliced Herbed Boneless Leg of Lamb with Mustard Crust on a platter.

FAQs

Can I use a bone-in leg of lamb instead of a boneless leg of lamb?

Yes! These seasonings would be great on any cut of lamb. For a bone-in leg of lamb, the cooking time might be a bit longer, so make sure to use that internal meat thermometer to check the temp as you go.

How do I get the panko crust to stick together?

Panko crust tends to be a little crumbly and fall apart. Moist elements like olive oil help the topping to stick to itself, and the seasoning on the meat should also help with sticking. If you’re really struggling, rub an extra teaspoon on the surface of the lamb or into the topping mixture. Ultimately, if you can’t get it all to stick, don’t worry! The bits that fall onto the baking sheet will get nice and crispy, and you can spoon the toasted topping back over the sliced lamb for serving.

Adjusting the Recipe for a Smaller Leg of Lamb

If you don’t have a big crowd, you can definitely make this with a smaller leg of lamb. Simply adjust the rest of the ingredients down proportionately (and don’t make yourself too crazy with the math — the amounts are really guidelines).

You’ll want to reduce the cooking time, too. For medium-rare, take the lamb out of the oven when the internal temperature is at 120 degrees F, and it will climb another 5 to 10 degrees as it sits, which will get you to those rosy pink slices.

An instant-read meat thermometer is a best friend in the kitchen. Of course, it’s really up to you how rare or well-done you like your meat. Do keep an eye on the internal temperature with a meat thermometer, as minutes can make a difference, and there are always the ends for people who like their meat more well done.

Sliced leg of lamb with a crust on a plate.

Leg of Lamb Leftovers

And if you don’t have a big crowd, but you do have a big leg of lamb? Leftovers! We got lamb crostini, Shepherd’s pie, and lamb soup out of our big, gorgeous roast; not a bit was wasted. Just ask my dog.

What to Serve With Herbed Boneless Leg of Lamb

Green Bean Salad with Clementine Oranges and Feta

Wild Rice Salad with Cranberries

Sweet Potato Spoon Bread

Herbed Boneless Leg of Lamb with Mustard Crust in baking dish on table.

More Leg of Lamb Recipes

Like this recipe? Pin it to your favorite board on Pinterest.

Pin This

Herbed Boneless Leg of Lamb with Mustard Crust

5 from 1 vote
Prep: 20 minutes
Cook: 1 hour 15 minutes
Total: 1 hour 35 minutes
Servings: 14 People
This leg of lamb, with its gorgeous crunchy mustard crust, is a showstopper.
Herbed Boneless Leg of Lamb with Mustard Crust / Mia / Katie Workman / themom100.com
Save Pin Print

Ingredients 

For the Lamb

  • 1 6–pound boneless leg of lamb (rolled and tied)
  • 6 peeled garlic cloves
  • Zest from 1 orange
  • ¼ cup fresh thyme leaves
  • 2 tablespoons fresh rosemary
  • Kosher salt and freshly ground pepper (to taste)
  • 3 tablespoons olive oil

For the Crust

  • ¼ cup Dijon mustard (coarse or smooth)
  • 2 tablespoons olive oil
  • 1 ½ cups Panko
  • ½ cup chopped fresh flat-leaf parsley

Instructions 

  • In a food processor, combine the garlic, orange zest, thyme, and rosemary. Puree, then add the olive oil and blend to make a paste. Smear the paste all over the lamb, place it in a container or deep bowl, cover, and refrigerate overnight.
  • Preheat the oven to 450 F. Meanwhile, let the lamb sit at room temperature for 30 to 45 minutes. Season the lamb with salt and pepper. In a small bowl, mix together the olive oil, mustard, and parsley, add the breadcrumbs, and use a spoon or your hands to thoroughly blend. Press the mixture all over the top and sides of the leg of lamb and place it in a roasting pan. Some of the panko mixture will fall off the sides; that’s fine; just kind of tuck it in underneath the sides of the lamb.
  • Roast the lamb for 15 minutes, then turn the oven down to 400 F and roast for another hour to an hour and 15 minutes, or until an instant-read thermometer inserted into the middle of the roast reads 120 to 125 F for medium-rare. Let the lamb sit for 20 minutes before slicing and serving warm.

Notes

Adjusting Recipe for a Smaller Leg of Lamb
If you don’t have a big crowd, you can definitely make this with a smaller leg of lamb; just adjust the rest of the ingredients down proportionately (and don’t make yourself too crazy with the math — the amounts are really guidelines).
You’ll want to reduce the cooking time, too.  For medium-rare, you want to take the lamb out of the oven when the internal temperature is at 120 degrees F, and it will climb another 5 to 10 degrees as it sits, which will get you to those rosy pink slices. 

Nutrition

Calories: 233kcal, Carbohydrates: 6g, Protein: 26g, Fat: 11g, Saturated Fat: 3g, Cholesterol: 78mg, Sodium: 175mg, Potassium: 395mg, Fiber: 1g, Sugar: 1g, Vitamin A: 227IU, Vitamin C: 5mg, Calcium: 31mg, Iron: 3mg

Nutrition information is automatically calculated, so should only be used as an approximation.

Like this? Leave a comment below!

Rate & Comment

Recipe Rating