Lamb leg requires around 25 minutes each pound at 350°F to reach medium roast; that I found in my own tries at least. Boneless bits cook a bit more quickly, almost 22 minutes each pound. The difference in amount of product truly matters: bone-in gives only 55 to 60% of cooked meat, while boneless reaches 72 to 75 percent.

That is a big toll.

How to Cook a Lamb Leg

For 10 guests, bone-in lamb leg needs around 10 pounds raw. For boneless, 6.5 pounds will be enough for the same amount. Every 3-ounce serving after cooking has about 162 calories and 23 grams of protein, with only 7 grams of fat.

With a fan oven you can remove around 15% of the whole cooking time… In my last 7-pound bit, it saved almost 20 minutes. And remmeber about the leftover heat: the lamb keeps cooking and rises yet 5 to 10 degrees during the 15 to 20 minute rest.

Pull it a bit early, to not go past the wanted time.

The info below does not come from some calculator or converter, it is based directly on real experiences and knowledge from cooking forums and groups.

Lamb leg is surprisingly flexible to use. Simple salt, pepper and olive oil works well. If you add broth and water in the roasting pan, everything stays nice and juicy, and you receive good base for those nice juices from the bred for sauce.

When you have time, slowly roasting the lamb at low temperature for around 5 hours, it becomes fall-apart soft. A slow cooker is another good option, that gives truly tasty and soft results.

Because it is a bit fatter, Mediterranean spice always works on roasted lamb leg. Boneless legs one can stuff with rosemary, parsley and garlic, later roll them and roast until perfect medium roast. Such dish perfectly works for festive dinners, especially at Easter.

Italians have another way: they use a marinade with garlic, rosemary and lemon.

Working with boneless leg, I always advise to remove extra inner fat. It helps to reduce the strong meaty taste, while you keep the juiciness. And do not forget the rest, leave the lamb sit on a rack for 10 minutes or more after coming from the oven, it does big difference before you carve.

Cutting boneless leg is easy: simply remove the string and cut freely.

Bone-in legs have their fans also. The classic way is rub with garlic, rosemary and mint, later roast until the surface is crusty and the inside juicy. Roasting at high heat gives you extra crisp potatoes with the lamb.

Or cut slits in the leg and tuck fresh rosemary with garlic.

Grilling and smoking both work well. Marinate boneless leg in red wine with garlic, onion, salt and pepper for some hours or overnight, later grill it hot and quickly until medium roast. Smoking bone-in leg adds truly interesting depth to the already rugged taste of lamb.

One way, with that I had luck, is smoke it at 225°F with dry rub applied two days before.

Lamb one can even cook in liquid for good result. For 2-3 hours in water with red wine, bay leaf, salt, garlic, mirepoix and rosemary, it becomes surprisingly soft. The meat simply falls apart on its own, so tying the roast is notalways needed for braising.

About serving sizes, a good rule says 1/2 to 2/3 pound each person for bone-in lamb leg. For boneless leg, go with around 1/3 pound each person. A 5-pound leg feeds around 10 people.

But it depends also on the appetites and how many other foods are on the menu.

In French, roasted lamb leg is called gigot d’agneau rôti. There is also a slowly cooked version called gigot of sept heures, which means that it cooks for 7 hours.