Step 1

Rub the lamb with olive oil and season with salt and pepper. Take the leg of lamb out of the refrigerator about an hour before cooking so it comes closer to room temperature. This promotes faster, more even cooking. Set the lamb in a rack inside a roasting pan. Drizzle with the olive oil and rub all over into the fat and meat. Season generously all over with salt and pepper. Position the lamb so that it is fat-side down.

Step 2

Broil for 5 minutes. Arrange an oven rack so that the top of the lamb is a few inches from the broiler element. Heat the broiler. Broil until the surface of the lamb looks seared and browned, about 5 minutes.

Step 3

Flip the lamb over and broil the other side. Flip the leg over and put back under the broiler until the other side is seared, about 5 minutes more.

Step 4

Top with garlic and rosemary. Take the lamb out of the oven. Turn off the broiler and set the oven temperature to 325°F. Reposition the oven rack to the middle of the oven. Rub the top of the lamb with the garlic and rosemary.

Step 5

Cover the lamb loosely with foil and roast 1 hour. Tent the pan loosely with aluminum foil to keep the garlic and rosemary from burning. Put the lamb back in the oven and roast for 1 hour.

Step 6

Uncover and take the temperature. Uncover the lamb. Take its temperature with an instant-read thermometer in the thickest part not touching bone. The lamb is ready when the temperature is 135°F or above. At 135°F the lamb is cooked to rare, but it will continue cooking as it rests, so we recommend taking it out of the oven at 135°F for medium-rare to medium. (Refer to the cooking chart above for general roasting times.)If the lamb is not ready, continue cooking uncovered until it reaches your desired internal temperature, checking the temperature every 20 minutes.

Step 7

Figure out where to carve. Let the lamb rest for at least 15 minutes before carving. Transfer the lamb to a clean cutting board. The bone runs through the meat at an angle, giving you two fairly big pieces of meat on either side of the bone. Start with the side of meat that feels most accessible to you.

Step 8

Cut the meat into slices across the grain. Make straight, parallel cuts straight down through the thickest part of the meat until you hit the bone. You should be cutting perpendicular to the bone, across the grain of the meat. The slices will still be attached where they meet the bone.

Step 9

Cut the slices off the bone. Turn your knife so that it's now parallel to the bone instead of perpendicular. Starting at the end of the bone furthest from you, cut through the slices where they attach to the bone. Keep your knife close to the bone so you get as much meat as possible, but don't worry about getting every single scrap of meat right now — just focus on cutting cleanly through the big slices and you’ll get any leftover pieces later.

Step 10

Transfer the slices to a serving platter. Place the slices on a serving platter. Tent the platter with foil to keep the meat warm.