Roasted Butterflied Leg of Lamb

Written by
Linda Larsen
Linda Larsen is a journalist, quick-cooking and slow-cooking expert, and accomplished cookbook author with over 30 years of experience in testing and developing recipes.
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Linda Larsen
Updated 12/20/20
Roasted Butterflied Leg of Lamb

The Spruce
Prep: 15 mins
Cook: 60 mins
Marinade: 24 hrs
Total: 25 hrs 15 mins
Servings: 10 to 12 servings
Nutritional Guidelines (per serving)
145 Calories
11g Fat
1g Carbs
10g Protein
See Full Nutritional Guidelines Hide Full Nutritional Guidelines
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Nutrition Facts
Servings: 10 to 12
Amount per serving
Calories 145
% Daily Value*
Total Fat 11g 14%
Saturated Fat 3g 16%
Cholesterol 35mg 12%
Sodium 303mg 13%
Total Carbohydrate 1g 0%
Dietary Fiber 0g 1%
Total Sugars 0g
Protein 10g
Vitamin C 2mg 10%
Calcium 11mg 1%
Iron 1mg 5%
Potassium 144mg 3%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
(Nutrition information is calculated using an ingredient database and should be considered an estimate.)

A leg of lamb is always a great cut to serve for a special meal. While it's usually cooked bone-in, a boneless leg of lamb is easier and faster to cook, and equally succulent and juicy. By asking your butcher to "butterfly" the leg, the resulting cut is a piece of lamb that can be cooked flat or rolled up. Sweet and gamey, our recipe brings you beautifully cooked lamb inside, with a crusty and delicious outer layer.

A fragrant marinade of mustard, herbs, and garlic flavors the meat. The result is a tender lamb that you can pair with any side dishes of your choice. We recommend simple accompaniments like roasted potatoes, grilled asparagus, and mint sauce. It is up to you to add other ingredients to the roasting pan: including sliced carrots, potatoes, zucchini, leeks, peppers, and eggplants can add to the flavor of the meat and be your side dish. Simply drizzle olive oil on the vegetables of your choice and season with salt and pepper.

Some recipes for a butterflied leg of lamb secure the meat with long skewers or kitchen twine, but we found that cooking the meat as-is also produces a lovely result, without the extra work. If you decide to secure the meat, run 2 long metal skewers lengthwise and 2 crosswise, or roll and tie the meat at 1 1/2 inch intervals. This recipe makes spectacular leftovers for sandwiches, salads, shepherd's pie, or stuffed pitas. Keep refrigerated and well covered for up to 3 days.

Ingredients

  • 2 teaspoons fresh thyme (stems removed, minced)

  • 2 teaspoons fresh rosemary leaves (minced)

  • 3 cloves garlic (minced)

  • 1 small onion (chopped)

  • 1/4 cup olive oil

  • 1/4 cup red wine vinegar

  • 2 tablespoons orange juice

  • 3 tablespoons Dijon mustard

  • 1 4 to 5-pounds leg of lamb (butterflied)

  • 1 teaspoon salt

  • Freshly ground black pepper (to taste)

Steps to Make It

  1. Gather the ingredients.

    Ingredients for roasted lamb
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  2. In a heavy duty zipper lock food storage bag, combine the thyme, rosemary, garlic, onion, oil, vinegar, orange juice, and mustard and mix well.

    Combine ingredients in ziploc bag
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  3. Place the leg of lamb in the marinade, seal the bag, and turn to coat. Massage the meat through the bag for a bit to help the marinade penetrate and coat all the meat evenly. Put the storage bag into a large roasting pan and marinate for 24 hours in the refrigerator.

    Massaging meat through the bag
    The Spruce

  4. Preheat the oven to 350 F. Remove the lamb from the marinade and place it in a shallow roasting pan. Season with salt and pepper.

    Lamb in glass tray
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  5. Roast the lamb, uncovered, for 50 to 70 minutes, basting it with the marinade several times during the process. Cook until an instant-read meat thermometer registers 145 F (for medium-rare) or 150 F (for medium) when inserted in the thickest part of the meat. For safety reasons, the lamb needs to be cooked to a minimum of 145 F.

    Roast the lamb
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  6. Remove the lamb from the oven, cover with foil, and let stand for 15 minutes before serving.

    Cover lamb with foil
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  7. Carve the lamb into slices against the grain. Plate, drizzle with the juices from the pan, and serve.

    Carve lamb into slices
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  8. Enjoy!

Different Marinades For the Lamb

The flavoring that you choose for the marinade is the flavor that your outer crust and meat will have. For a smoother texture in your marinade, simply blend all of the ingredients at high speed until well incorporated. Fresh herbs like the ones we used, and even their dried counterparts, are great complements to lamb, but other flavors can be used when marinating this butterflied leg of lamb:

  • Replace the mustard in our marinade with 3 finely chopped anchovies.
  • Use the zest of one small orange or lemon in addition to the rest of the marinade ingredients.
  • Make a marinade using 1/3 cup of sesame oil, 2 tablespoons of honey, 2 tablespoons of lemon juice, 2 to 3 tablespoons of chopped mint, 1/4 white wine vinegar, and salt and pepper to taste.
  • Use 1/3 cup of olive oil, 1/3 cup of good quality balsamic vinegar, 2 minced garlic cloves, 1 shallot finely minced, and 1 tablespoon each of dried thyme, oregano, sage, and rosemary.

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