Roast Leg of Lamb

The most important thing to remember about cooking a lamb roast is to not over-cook it. Lamb has such wonderful flavor on its own, and is so naturally tender, that it is bound to turn out well, as long as it is still a little pink inside.

There is some debate over which method yields the best results—slow cooking at low heat the entire time, or searing first on high heat and then slow cooking. James Beard in his American Cookery prefers the slow-cook-low-heat method (he rubs the roast with salt and pepper and cooks it at 325°F the whole time.)

We generally get great results with the searing method, starting at high heat and then dropping the temp which is the method described in the following recipe. If you use searing method, you will have ends that are more well done, and as you get closer to the interior, more rare. This way you have a variety to serve to guests.

Another point where there are wildly varying opinions is the internal temperature that constitutes “medium rare”. I’ve seen references that range from 120° to 145°F. For this roast, I pulled it out at 125°F. As it rested the internal temperature continued to rise a few points as the meat continued to cook.

We like lamb on the rare side of medium rare, and this roast was perfectly done to our taste. Clearly an accurate meat thermometer is essential, and it helps to insert the meat thermometer at different places into the deep interior of the roast to get a good read.

A great way to keep tabs on how well the roast is cooking is to use a remote thermometer. This way you can tell when the roast is done without having to open the oven door, avoiding the loss of heat that comes from doing that.

These directions assume that you have let the roast sit at room temperature for an hour or two before roasting. If you are taking a roast and cooking it directly from the fridge, it will take longer to cook.

Updated from the recipe archive, first posted 2006.

Roast Leg of Lamb Recipe

The marinade we used on this roast comes from my friend Suzanne and it works quite well. A simpler marinade of rosemary, olive oil, garlic, pepper, and lemon juice would do the trick quite nicely too. One can also make tiny slices into the surface of the roast and insert slivers of garlic and herbs.

Ingredients

Marinade

• 1/2 cup orange juice
• 1 cup white wine
• 3 cloves garlic, minced
• 2 teaspoons of fresh thyme or 1 teaspoon of dried thyme
• 2 Tbsp of fresh chopped rosemary or 1 Tbsp of dried rosemary
• 1/4 teaspoon of fresh ground pepper

Blend marinade ingredients in a blender, just a few pulses until well mixed.

Lamb Roast

• One 6-pound leg of lamb, bone-in or boneless. (If boneless, the leg should be tied up with kitchen string by butcher.)
• Marinade
• Salt and freshly ground black pepper

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