Leg Recipe

Bring to room temperature

Remove the leg of lamb from the refrigerator 45–60 minutes before cooking so it comes close to room temperature. Pat dry with paper towels.

Preheat oven

Preheat oven to 200°C (400°F). Position a rack in the middle of the oven.

Prepare the herb-garlic paste

In a small bowl combine minced garlic, chopped rosemary, chopped thyme, lemon zest, Dijon mustard, olive oil, kosher salt and black pepper. Mix to form a thick paste.

Score and season

If the leg has a fat cap, score the fat in a diamond pattern with a sharp knife (1 cm deep). Rub the herb-garlic paste all over the surface of the lamb, pressing it into the scored fat and any crevices so it adheres well.

Roast

Place the leg on a rack set in a roasting pan, fat-side up. Insert an oven-safe meat thermometer into the thickest part without touching bone. Roast at 200°C (400°F) for 15 minutes to develop color, then reduce oven temperature to 180°C (350°F). Continue roasting until desired doneness: about 15–18 minutes per 500 g for medium-rare (internal temp 55–58°C / 130–136°F), 20–22 minutes per 500 g for medium (60–65°C). For a 1 kg leg expect roughly 30–36 minutes after initial high-heat sear for medium-rare. Monitor thermometer closely.

Rest

When the lamb reaches target temperature, remove it from the oven and transfer to a cutting board. Tent loosely with foil and let rest for 15–20 minutes (internal temp will rise a few degrees). Resting ensures juices redistribute.

Carve

Carve the leg against the grain into 1 cm–1.5 cm thick slices. Serve immediately with pan sauce if using.

While the lamb rests, place the roasting pan on the stovetop over medium-high heat. If there is a lot of fat, spoon off excess leaving roughly 2 tablespoons of drippings.

Add the red wine or stock to the hot pan to deglaze, scraping up browned bits with a wooden spoon. Add rosemary and thyme sprigs and simmer until the liquid is reduced by about half, about 3–5 minutes.

Strain the sauce into a small saucepan or bowl, discarding herbs and solids. Whisk in 1 tablespoon butter off heat until glossy. Season to taste with salt and pepper. Spoon sauce over carved lamb.