To make a roasted 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 flavorful. The leftovers are excellent, too, reheated or cold.
Lamb is my favorite meat. I love its distinctive flavor and especially enjoy its fat - I find it more palatable than beef fat. I cook lamb recipes often, including lamb steak, lamb burgers, lamb meatballs, and rack of lamb.
When I want to cook a big piece of meat for a holiday or a large gathering, my most common choices are pork roast, beef tenderloin roast, ribeye roast, or leg of lamb.
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Ingredients
You'll only need a few simple ingredients to make this recipe. 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. If you use extra-virgin olive oil, it should be fine at the temperatures we use in this recipe.
- To season: I use kosher salt, black pepper, garlic powder, dried cumin, and dried rosemary.
- Leg of lamb: I typically use a 4-pound semi-boneless roast imported from Australia. I get it at my local grocery store (Safeway).
Variations
- Instead of olive oil, I sometimes use melted butter or ghee.
- Use fresh minced garlic instead 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. A teaspoon of smoked paprika is also great in this recipe, and so is a teaspoon of ground fennel seeds.
Instructions
Scroll down to the recipe card for detailed instructions. Here are the basic steps for making this recipe:
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 lamb in a roasting pan on a greased rack. Let it rest at room temperature for one hour.
Insert the probe of an oven-safe meat thermometer into the thickest part of the lamb, ensuring it isn't touching the bone. Set the thermometer to 135°F.
Preheat your oven to 425°F. Roast the lamb for 15 minutes in the 425°F oven. This initial high-heat roasting will brown the fat cap.
Lower the oven temperature to 375°F and continue roasting until the thermometer alerts you that the lamb is done. 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 slicing and serving.
Expert Tips
- If your lamb is bigger than 4 pounds, it will need to spend more time in the 375°F oven - as mentioned above, about 20 minutes per pound after the first 15 minutes at 425°F. In this case, 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 pounds, increase the olive oil and spices accordingly. So, for example, if your lamb is 6 pounds, increase them by 50%.
- As with all roasts, allowing the meat to rest for at least 15 minutes before slicing is important. 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.
Recipe FAQs
Roasting is the best method. This cut of meat has a beautiful fat cap, and cooking it in the oven browns it nicely.
You could, but it's 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 (425°F), then lowering the oven to 375°F and continuing to roast until the lamb is cooked.
You want to ensure the meat stays medium-rare (although 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 an oven-safe meat thermometer when roasting - the type of thermometer that beeps to alert you when the lamb has reached the desired internal temperature.
Serving Suggestions
Any side dish goes with this roast. It's a very versatile main course. I often serve it with one or two of the following side dishes:
Storing Leftovers
You can keep the leftovers in the fridge, in a sealed container, for up to 4 days. They are excellent when gently reheated in the microwave, covered, at 50% power. But don't overcook them, or they'll become dry.
I also enjoy eating cold slices of the leftovers with quick pickles, Dijon mustard, or sriracha mayo.
More Lamb Recipes
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Recipe Card
Roasted Leg of Lamb
Ingredients
- 3 tablespoons olive oil
- 2 teaspoons Diamond Crystal kosher salt - or 1 teaspoon of any other salt
- ¼ teaspoon black pepper - freshly ground
- 1 teaspoon garlic powder
- 1 teaspoon dried rosemary
- ½ teaspoon ground cumin
- 4 pounds leg of lamb - semi-boneless
Instructions
- Mix the olive oil, salt, pepper, garlic powder, dried rosemary, and ground cumin in a small bowl.
- 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 one hour.
- Preheat your oven to 425°F. Insert an oven-safe meat thermometer into the thickest part of the lamb without allowing it to touch the bone. Set the thermometer to 135°F (medium-rare). Roast the lamb for 15 minutes in the preheated 425°F oven.
- Lower the oven temperature to 375°F and continue roasting until the thermometer alerts you that the meat has reached an internal temperature of 135°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 slicing and serving.
Video
Notes
- If your lamb is bigger than 4 pounds, 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 pounds, increase the olive oil and spices accordingly. So, for example, if your lamb is 6 pounds, increase them by 50%.
- The nutrition info is from the USDA database.
- The USDA says you should cook roasts to medium (145°F).
- You can keep the leftovers in the fridge, in a sealed container, for up to 4 days. They are excellent when gently reheated in the microwave, covered, at 50% power. But don't overcook them, or they'll become dry. I also enjoy eating cold slices of the leftovers with quick pickles, Dijon mustard, or sriracha mayo.
Nutrition per Serving
Disclaimers
Cup measurements refer to the standard American cup, which is 240 milliliters. Most of my recipes are low-carb (or keto) and gluten-free, but some are not. Please verify that a recipe fits your needs before using it. Recommended and linked products are not guaranteed to be gluten-free. Nutrition info is approximate, and the carb count excludes non-nutritive sweeteners. Nutrition info may contain errors, so please verify it independently. Recipes may contain errors, so please use your common sense when following them. Please read these Terms of Use carefully before using any of my recipes.
Vered DeLeeuw, LL.M., CNC, has been following a low-carb real-food diet and blogging about it since 2011. She's a Certified Nutrition Coach (NASM-CNC), has taken courses at the Harvard School of Public Health, and has earned a Nutrition and Healthy Living Certificate from Cornell University. Her work has appeared in several major media outlets, including Healthline, HuffPost, Today, Women's Health, Shape, and Country Living. 
Rachel
Thank you for this recipe! The lamb was wonderful! I did use fresh garlic also. I will make this again.
Vered DeLeeuw
You're very welcome, Rachel! Thank you for sharing your tweaks.
Jim Holland
This leg of lamb was easy to make and very juicy. I enjoyed the flavor of the spices. My wife and I have lots of leftovers to use in sandwiches. Thank you for a great recipe!
Vered DeLeeuw
You're very welcome, Jim!
N
The one I have says boneless, does that change the instructions at all? Thanks.
Vered DeLeeuw
Hi,
You can use the same instructions for a boneless leg of lamb. Please use an oven-safe meat thermometer.