ROAST LEG OF LAMB

THE MAIN PROBLEM WITH ROAST LEG OF lamb is that it cooks unevenly. In most cases, the outer meat becomes dry and gray, while the meat around the bone remains almost raw. Since the leg is reasonably priced and feeds a lot of people, it seemed worth solving this basic cooking problem.

The uneven thickness of the leg is the most formidable obstacle to even cooking. At the thicker sirloin end, the meat surrounding the flat, twisting hipbone is very thin. The center of the leg, which comprises the top half of the thigh, is fleshy, but the thigh then tapers dramatically toward the knee joint, and the shank itself is a mere nub of meat.

The only way to deal with the problem is to remove the hipbone entirely and then tie the leg into as compact a shape as possible. However, boning and tying do not by themselves guarantee even cooking. Special procedures must be followed in roasting the leg to ensure that all parts are exposed to the same amount of heat and will thus reach similar internal temperatures at the same time.

We started by roasting a 7¹/₂-pound leg at 400 degrees, with the meat resting directly on the roasting pan. After about one hour, the meaty side of the leg, which had been facing up, registered 120 on a meat thermometer, or underdone. The meat around the thigh bone was practically raw, while the bottom of the leg, which had been resting on the hot pan, had reached 135 degrees, or slightly overdone.

Clearly we needed a rack to protect the downward-facing side of the leg from overcooking. We also felt the exterior could be browner and that a lower cooking temperature might even out the rate at which various parts of the leg cook. We roasted a leg on a rack at 450 degrees for 20 minutes and then lowered the temperature to 325 degrees for the next hour. The top was evenly cooked, at 130 degrees throughout, but the underside was undercooked. Evidently, the rack had been too effective in keeping the bottom of the leg cool.

We decided to try the next leg with the oven rack at the lowest position, so that the rack side of the leg might cook more quickly. This helped, but we decided in the end that the leg would have to be turned for even cooking.

We had one final question: Was it worth trying to find Prime rather than the standard Choice lamb. Tasting them side-by-side, we preferred the Prime cut, which was more tender. The Choice leg was a bit chewy, while the Prime leg was silky and buttery. The flavor of the Prime leg was also less gamy and richer, almost like roast beef. The differences, especially in texture, were most apparent in slices taken from the rarest portion of the roasts. So if you like rare lamb, it's definitely worth ordering a Prime leg. It only costs an extra 50 cents or so a pound, but you will have to find a butcher shop that carries this sometimes hard-to-find meat.