Description

This Slow-Roasted Boneless Leg of Lamb recipe features a tender, flavorful lamb leg seasoned with a garlic, rosemary, and anchovy mixture. Butterflied and slow-cooked at a low temperature, the lamb develops a succulent, medium-rare interior with a crisp, deeply browned crust from a high-temperature finish. Perfect for feeding a crowd, this dish combines delicate herbs and spices with an elegant roasting technique for a memorable centerpiece.

Ingredients

Seasoning Mixture

2 tablespoons (30 ml) extra-virgin olive oil
3 medium cloves garlic (1/2 ounce; 15 g), minced (about 1 tablespoon)
1 medium shallot, minced (about 1/2 cup)
6 anchovy filets (11 g), minced (about 1 1/2 tablespoons)
2 tablespoons (8 g) finely chopped fresh rosemary leaves
1 tablespoon (6 g) finely grated lemon zest (from 1 lemon)
1/2 teaspoon red pepper flakes
2 tablespoons (18 g) Diamond Crystal kosher salt (use half as much by volume or the same weight if using table salt)
Freshly ground black pepper, to taste

Lamb

1 (6- to 8-pound) boneless leg of lamb, butterflied to even 1-inch thickness and trimmed of excess fat

Instructions

Prepare the Oven and Seasoning Mixture: Adjust the oven rack to the lower-third position and preheat oven to 275°F (135°C). In a small saucepan over medium heat, warm the olive oil until shimmering, about 3 minutes. Add minced garlic, shallot, anchovies, rosemary, lemon zest, and red pepper flakes. Cook, stirring occasionally, until the shallots and garlic soften, about 3 to 5 minutes. Transfer the mixture to a small heatproof bowl, then stir in kosher salt and freshly ground black pepper.
Season the Lamb: Rub half of the seasoning mixture inside the butterflied lamb leg. Roll the lamb leg tightly and secure it with butcher’s twine at 1-inch intervals. Rub the remaining seasoning mixture over the exterior of the rolled lamb. You may either cook it immediately or let it rest uncovered in the refrigerator for up to 12 hours to enhance flavor and texture.
Slow Roast the Lamb: Place the prepared lamb leg fat side up on a wire rack set in a foil-lined rimmed baking sheet. Transfer to the oven and roast until an instant-read thermometer inserted into the thickest part reaches 125°F to 130°F (52° to 54°C) for medium-rare or 130°F to 135°F (54° to 57°C) for medium doneness, about 2 1/2 to 3 hours.
Rest the Lamb: Remove the lamb from the oven and let it rest uncovered for 40 minutes. This resting time allows the juices to redistribute evenly throughout the meat.
Finish with High-Heat Roast: While the lamb is resting, increase the oven temperature to 500°F (260°C). Return the lamb to the oven and roast for about 15 minutes until the exterior is deep golden brown and crisp.
Final Rest and Serve: Remove the lamb from the oven and let it rest for 5 minutes. Cut the butcher’s twine using kitchen shears, transfer the lamb to a cutting board, and slice into 1/4-inch thick pieces. Serve immediately for best flavor and texture.

Notes

Butterflying the lamb to an even thickness is key for uniform cooking.
Letting the seasoned lamb rest in the refrigerator overnight enhances flavor penetration.
Use an instant-read thermometer to ensure perfect doneness.
Resting the lamb both before and after the final high-heat roast keeps the meat juicy.
Adjust salt quantity if using different types of salt; Diamond Crystal kosher salt is less dense than table salt.