Roasted Boneless Leg of Lamb with Mushroom Cream Sauce

Photo by Michael Piazza / Styled by Catrine Kelty

Growing up, a roasted leg of lamb with a side of flageolet beans and roasted new potatoes was always part of our Easter Sunday meal. It was a sign of spring and the promise of warm days ahead. My father would prepare the lamb a few weeks ahead of time, air drying it suspended on a wire in the walk-in fridge at his butcher shop. This was a tender process: He would watch it every day, trimming fat here and there, resulting in a beautiful, tasty piece of meat. A leg of lamb is a household favorite, always part of our welcoming spring celebration. Mine is boneless for simplicity; I get extra flavor from a mustard paste.

Serves 6–8 with leftovers

1 (4-pound) boneless leg of lamb, trimmed of excess fat and tied
freshly cracked black pepper
2 tablespoons Dijon mustard
5 garlic cloves, minced
1 tablespoon olive oil
1 teaspoon soy sauce
1 tablespoon minced fresh rosemary, plus extra sprigs for garnish
sea salt, to taste

For the sauce:
2–3 tablespoons unsalted butter
1 shallot, minced
3 cups sliced shiitake mushrooms
1 cup white wine
2 teaspoons Dijon mustard
½ cup heavy cream

Prepare the leg 6 hours, or up to a day, ahead: Liberally season the lamb with cracked pepper on all sides. In a bowl, whisk the rest of the ingredients into thick paste. Spread the mixture on all sides of the leg, wrap in plastic or in a resealable bag and refrigerate until ready to roast.

When ready to cook, unwrap the leg, place in a roasting pan and let sit at room temperature for 30 minutes. Preheat oven to 425°F.

Season the lamb with salt and pepper. Roast for 15 minutes, then reduce the temperature to 350°F and cook for another hour, until the temperature of the leg registers 130°–135°F.

Meanwhile, prepare the sauce: Melt the butter in a sauté pan. Add the shallot and mushrooms, sauté until soft and golden, about 6 minutes; if the pan gets dry, add another tablespoon of butter. Slowly add the wine; let it bubble, scraping any browned bits from the bottom of the pan, reduce the heat to medium and let the liquid reduce by half. Add the mustard, mixing well, then slowly add the cream. Bring to a simmer, turn off the heat and set aside.

When the lamb reaches 130°F–135°F transfer to a cutting board, tent with foil and let rest for 10 minutes. Return the roasting pan to the top of the stove. Over medium heat add ½ cup of white wine or stock and scrape up any brown bits left in the pan. Reduce the heat and add the mustard-cream sauce, mixing well.

Slice the lamb into ½-inch-thick slices and arrange on a serving platter. Garnish with rosemary sprigs and stir any accumulated juices from slicing the meat into the sauce. Serve lamb with sauce, roasted fingerling potatoes and steamed asparagus.

This recipe appeared in the Spring 2019 issue as part of a larger story on lamb.