Leg Of Lamb Cooking Time Per Pound

To roast a leg of lamb, simply rub it with olive oil and spices, then cook it to medium-rare (135°F) in a 375°F oven.

The result is tender, juicy, and very flavorful! Leftovers are excellent too, heated up or even cold.

A sliced leg of lamb served on a white plate.

Lamb is by far my favorite meat. I love its distinctive flavor, and I especially enjoy its fat - I find it more palatable than beef fat.

I have quite a few lamb recipes that I make regularly. But when I want to roast a big piece of meat, for a holiday or for a large gathering, my two most common choices are either roasting a whole leg of lamb or making ribeye roast.

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Ingredients
Instructions
Expert tips
Frequently asked questions
Variations
Serving suggestions
Storing leftovers
Related recipes
Recipe card

Ingredients

You'll only need a few simple ingredients to make this tasty roast. The exact measurements are included in the recipe card below. Here's an overview of what you'll need:

Olive oil: This is my favorite oil to cook with and it goes amazingly well with lamb. But if you'd rather use an oil with a higher smoke point, you can use avocado oil instead.

Kosher salt and black pepper: If using fine salt, you should reduce the amount you use, or the dish could end up too salty.

Spices: I like to use garlic powder, dried cumin, and dried rosemary.

Leg of lamb: I typically use a 4 lb. semi-boneless piece, imported from Australia. I get it at my local grocery store (Safeway).

Instructions

How to cook a leg of lamb? My favorite method is to roast it in the oven, and it's surprisingly easy! Scroll down to the recipe card for detailed instructions. Here are the basic steps:

In a small bowl, mix together the olive oil, salt and pepper, garlic powder, cumin, and rosemary.

Rub the mixture all over the lamb. Place the meat in a roasting pan on a greased rack. Let it rest at room temperature for one hour.

Preheat your oven to 425 degrees F. Roast the lamb for 15 minutes in the 425-degree oven.

Lower the oven temperature to 375 degrees F and continue roasting until an instant-read thermometer inserted in the thickest part and not touching the bone registers 135 degrees F for medium-rare. This should take about 1 hour and 20 minutes (20 minutes per pound).

Remove the lamb from the oven, cover it loosely with foil, and allow it to rest for 20 minutes before carving.

A photo collage showing the steps for roasting a leg of lamb.

Expert tips

Here are a few tips to ensure this recipe is a success:

If your lamb is bigger than 4 lb. it will need to spend more time in the 375F oven - as mentioned above, about 20 minutes per pound after the initial 15 minutes at 425F. If this is the case, it's a good idea to loosely cover it with foil after it's spent about an hour and a half in the oven. Otherwise, the top could get too dark.
If the roast is significantly larger than 4 lb. (say, 6 lb.), you can increase the olive oil and spices by 25%.
As with all roasts, it's important to allow the meat to rest for at least 15 minutes before slicing it. You want to give the juices a chance to settle and redistribute before you cut into the meat. There's nothing more depressing to a foodie than cutting into a juicy piece of meat and watching all the yummy juices escape to the cutting board.

Frequently asked questions

What's the best way to cook a leg of lamb?

Roasting is the best method. This cut of meat has a wonderful fat cap and cooking it in the oven browns it nicely.

Sure, you could use a slow cooker. But in my opinion, it won't be as good. The fat cap won't brown, and the lean meat can easily dry out during prolonged cooking.

What's the cooking time for a leg of lamb?

a 4-lb. semi-boneless piece will need to spend about one and a half hours in the oven: 15 minutes in a 425F oven to brown the fat cap, then 20 more minutes per pound in a 375F oven (so an additional 1 hour and 20 minutes).

Keep in mind that you also need to bring the meat to room temperature first, which takes about an hour. And after it's done, it needs to rest for about 20 minutes before you carve it. So all in all, this recipe takes about 3 hours from start to finish.

Should I sear the meat before roasting it?

You could, but it's really not a fun thing to do and I don't think it's necessary.

You can achieve a similar result by roasting it briefly at a high temperature (425F), then lowering the oven to 375F and continuing to roast until the meat is cooked.

What level of doneness is best?

You want to make sure that the meat stays medium-rare (although I should note that the USDA says you should cook roasts to medium).

Any more than that, especially if it's cooked to more than medium, and it becomes dry and tough and loses much of its flavor. So it's best to use a meat thermometer when roasting.

Variations

I love this recipe as is and almost always make it as written. But in case you'd like to vary the basic recipe, here are a few ideas for you:

Instead of olive oil, you can use melted butter.
Use fresh minced garlic insteasd of garlic powder, as I do in the video below.
Vary your spices. I typically use garlic powder, dried cumin, and dried rosemary. But in the video I use dried thyme instead of cumin and fresh garlic instead of garlic powder. Smoked paprika is another tasty option.

Serving suggestions

Any side dish goes with this recipe. It's a very versatile main course. I often serve it with one or two of the following side dishes:

Roasted vegetables
Roasted green beans
Mashed cauliflower

Storing leftovers

You can keep the leftovers in the fridge, in a sealed container, for up to 4 days. They are very good when gently reheated in the microwave, covered, on 50% power.

But make sure you don't overcook them or they'll become dry and inedible. I also enjoy eating cold slices of the leftovers with some homemade quick pickles.

A roasted leg of lamb, sliced, served on a white plate.

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Recipe card

Oven-Roasted Leg of Lamb

To oven-roast a leg of lamb, simply rub it with olive oil and spices, then cook it to medium-rare (135°F). The result is tender, juicy, and very flavorful!

Prep Time 10 mins

Cook Time 1 hr 20 mins

Rest time 1 hr 20 mins

Total Time 2 hrs 50 mins

Course: Main Course

Cuisine: Greek

Servings: 8 servings

Calories: 477 kcal

▢ 3 tablespoons olive oil
▢ 2 teaspoons Diamond Crystal kosher salt or 1 teaspoon fine salt
▢ ¼ teaspoon freshly ground black pepper
▢ 1 teaspoon garlic powder
▢ 1 teaspoon dried rosemary
▢ ½ teaspoon ground cumin
▢ 4 lb. leg of lamb semi-boneless

In a small bowl, mix together the olive oil, salt, pepper, garlic powder, dried rosemary, and ground cumin.
Rub the olive oil mixture all over the meat. Place the lamb, flat side down and fat cap up, in a rimmed roasting pan on a greased rack. Allow it to rest on the counter, at room temperature, for 1 hour.
Preheat your oven to 425 degrees F.
Insert a meat thermometer into the thickest part of the meat without allowing it to touch the bone. Set the thermometer to 135 degrees F (medium-rare). Roast the lamb for 15 minutes in the preheated 425-degree F oven.
Lower the oven temperature to 375 degrees F and continue roasting until the thermometer alerts you that the meat has reached an internal temperature of 135 degrees F. This should take about 1 hour and 20 minutes (about 20 minutes per pound).
Remove the lamb from the oven, cover it loosely with foil, and allow it to rest for 20 minutes before carving.

If your lamb is bigger than 4 lb. it will need to spend more time in the 375°F oven - as mentioned above, about 20 minutes per pound after the initial 15 minutes at 425°F. If this is the case, it's a good idea to loosely cover it with foil after it has spent an hour and a half in the oven. Otherwise, the top could get too dark.

If the roast is significantly larger than 4 lb. (say, 6 lb.), you can increase the olive oil and spices by 25%.

Nutrition info is approximate, taken from fitday.com, and assumes that the lamb is imported and that both the lean and the fat are eaten.

It should be noted that the USDA says that you should cook roasts such as this to medium (145 degrees F).

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