This is how to roast a leg of lamb perfectly every single time. With a simple garlic butter marinade, this meat is tender, juicy, and cooked to perfection. Serve with a side and bread for a complete meal. Leftovers are great for sandwiches and wraps.
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Are you afraid of roasting meat? Especially cuts like a leg or lamb shoulder? Well, don't be. In fact, they are easy once you know the right method and technique.
The one thing that gave me confidence with roasting, was buying my meat thermometer. In fact, I highly recommend you buy this one. This takes the guesswork out. And, it means that you don't have to calculate the meat and the cooking time. Also, it means you don't have to open the oven door every time to check on it. In addition, the best thing is you are not stressed anymore.
Why make this leg of lamb
- This is the easiest no-fuss roast lamb to make any time of the year. Plus, there is so much to love about this roast.
- Today, I am using a garlic butter marinade, but, no matter what marinade you use, you can use the same process to roast lamb successfully every single time.
- Most of the ingredients used are simple pantry staples plus fresh herbs.
- You can marinate the meat for as little as 15 to an hour, or up to 12 hours in the fridge.
- Today, I am using bone-in lamb leg but you can also use boneless leg of lamb or lamb shoulder with this marinade.
- The process for roasting this lamb is very simple too.
- Make the garlic butter marinade - 5 mins
- Marinate the lamb - 15 mins up to 12 hours.
- Roast the lamb - 1 to 1 ½ hours
- Rest the lamb - 15 mins
- Make gravy - 10 mins
- You can use leftover lamb for sandwiches and wraps or in my chicken pot pie or shepherd's pie.
Ingredients and substitutes
- Lamb - I am using a bone-in leg of lamb. But, you can also use the shoulder for this recipe. Just make sure to thaw the meat an hour or two before roasting.
- Butter - Adds flavor and keeps the lamb moist and tender. Plus, the gravy is absolutely delicious.
- Herbs - For red meat, it is very important to use fresh herbs. And yet, you can also use 1 teaspoon dry rosemary and 1 teaspoon dry thyme in the marinade.
- Garlic - This has to be fresh garlic. As you can see, we do have a nice generous portion of garlic for flavor.
Step by step instructions
- Marinade - In a small bowl combine butter, garlic, thyme, rosemary, salt, and pepper
- Lamb - Trim excess fat off the lamb and pat dry on all sides.
Pro tip - if the lamb is wet the marinade will slide off the meat as soon as it starts cooking. If the meat was frozen ensure that it is thawed at least an hour before marinating. - Season the lamb with salt and pepper. Then, marinate it with the garlic butter marinade.
Pro tip - Leave to marinate for an hour on the counter or up to 12 hours in the fridge. This recipe can be roasted even without marinating but if you have the time it is always recommended.
- Preheat the oven at 350°F / 180°C / Gas mark 4
- Place the leg of lamb in a roasting pan on the roasting rack.
Pro tip - If using a thermometer like me add it in the center in the thickest part of the meat. - Add ¼ cup water to the roasting rack.
Pro tip- adding the water will prevent the melted butter marinade from burning/smoking as it drips into the pan.
- Roast until you reach the desired temperature of doneness.-
- Medium rare - between 130 F to 135 F, approximately 20 minutes per pound.
- Medium - between 135 F to 140 F, approximately 22 to 23 mins per pound
- and Medium well - between 145 F to 150 F, approximately 25 minutes per pound
- Well Done is between 155 to 165 F, approximately 30 minutes per pound.
- When the thermometer reaches your desired temperature, remove the lamb out of the oven. Loosely tent it with aluminum foil and let rest for at least 15 minutes before slicing. In the meantime make the gravy.
Gravy
- Place the roasting pan over medium heat and add the stock. Deglaze the pan by scraping off as much as you can from the pan
Pro tip - use a wooden or silicone spatula so you don't ruin our roasting rack. Do not scrape the burnt black parts just so you don't add a burnt taste to the gravy. - Add the flour and continue to cook until it thickens. Strain through a sieve or mesh to remove all the unwanted herbs, etc. Serve alongside the meat.
More lamb recipes
- Leg of lamb with Garlic Herb Oil Marinade
- Garlic butter leg of lamb
- Lamb Shoulder in red wine
- Standing prime rib roast
- Grilled Lamb chops or Lamb chops with balsamic glaze
- See all lamb recipes
Sides to go with leg of lamb
- Roast potatoes or mashed potatoes.
- rice pilaf with dried fruit and nuts,
- Salad - Cherry Tomato Mozzarella, Cabbage, Celery, Carrot Salad.
- Quick garlic sesame asparagus or garlic Parmesan asparagus,
- Swiss chard patties, sesame green beans,
- oven-baked butternut squash, oven-baked carrot sticks.
Frequently asked questions
If stored properly, a roast leg of lamb will keep in the fridge for 3 to 4 days. You can also freeze it for up to a month.
A leg of lamb can be boneless or bone-in. It is a very impressive and often expensive cut of meat that comes from the back haunches of the lamb.
As a guide, you should look for an average weight of about 5 to 7 pounds. Don't buy a baby lamb and dont' buy an old lamb which may be too tough when cooked.
Also, ask the butcher to trim the outer tough layer of fat. But, dont' remove all fat, you need some for flavor and to keep the meat moist and tender.
I personally prefer to use a meat thermometer so I don't have to calculate and watch the clock ever so often. But, you can certainly do without it. However, if you are new to cooking or roasting meat, a thermometer can take the guesswork out. The most important point to note is to make sure you insert the thermometer needle in the middle deepest part of the thick meat.
I cook my lamb medium-rare, about 135 F, using a meat thermometer. But, if you don't own a thermometer here's a guide you can use.
- Medium rare - between 130 F to 135 F, approximately 20 minutes per pound.
- or Medium - between 135 F to 140 F, approximately 22 to 23 minutes per pound.
- and Medium well - between 145 F to 150 F, approximately 25 minutes per pound.
- Well Done is between 155 to 165 F, approximately 30 minutes per pound
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Printable Recipe
How to roast Leg of Lamb
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Ingredients
- 5 lbs (2.25 kg) Leg of lamb (bone in)
- 4 tablespoon Butter unsalted
- 6 Garlic cloves
- 2 sprig Rosemary leaves removed
- 4 sprigs Thyme leaves removed
- 1 teaspoon Salt
- 1 teaspoon Pepper
Gravy
- 1 tablespoon All-purpose flour
- ½ cup Stock (or white wine)
Instructions
- Marinade - In a small bowl combine butter, garlic, thyme, rosemary, salt, and pepper
- Lamb - Trim excess fat off the lamb and pat dry on all sides. Pro tip - if the lamb is wet the marinade will slide off the meat as soon as it starts cooking. If the meat was frozen ensure that it is thawed at least an hour before marinating.
- Season the lamb with salt and pepper. Then, marinate it with the garlic butter marinade.Pro tip - Leave to marinate for an hour on the counter or up to 12 hours in the fridge. This recipe can be roasted even without marinating but if you have the time it is always recommended.
- Preheat the oven at 350°F / 180°C / Gas mark 4
- Place the leg of lamb in a roasting pan on the roasting rack. Pro tip - If using a thermometer like me add it in the center in the thickest part of the meat.
- Add ¼ cup water to the roasting rack.Pro tip- adding the water will prevent the melted butter marinade from burning/smoking as it drips into the pan.
- Roast until you reach the desired temperature of doneness.- Medium rare - between 130 F to 135 F, approximately 20 minutes per pound.- Medium - between 135 F to 140 F, approximately 22 to 23 mins per pound - Medium well - between 145 F to 150 F, approximately 25 minutes per pound- Well Done is between 155 to 165 F, approximately 30 minutes per pound.
- When the thermometer reaches your desired temperature, remove the lamb out of the oven. Loosely tent it with aluminum foil and let rest for at least 15 minutes before slicing. In the meantime make the gravy.
Gravy
- Place the roasting pan over medium heat and add the stock. Deglaze the pan by scraping off as much as you can from the panPro tip - use a wooden or silicone spatula so you don't ruin our roasting rack. Do not scrape the burnt black parts just so you don't add a burnt taste to the gravy.
- Add the flour and continue to cook until it thickens. Strain through a sieve or mesh to remove all the unwanted herbs, etc. Serve alongside the meat.
Recipe Notes
- You want to choose a well-marbled piece of meat with a decent amount of fat on top. The fattier the meat the more juicy and flavorful the roast.
- Always thaw the lamb before cooking - at least 2 to 3 hours. Cooking chilled meat can result in uneven baking causing the outer parts of the meat to overcook.
- A leg is a large chunk of meat and not much exposed. So, make sure to over-season the meat, because only some of it will penetrate the meat. The rest of it will get crusted on.
- Use a roasting rack, don't just place the meat on the baking tray. The roasting rack will let the juices flow below and let the outside of the leg forms a crust almost a sear that keeps all the juices in.
- Elevate the bone from the base if possible. This encourages even cooking by circulating the air.
- Cook the meat just until you reach the desired doneness, not a minute more. The meat continues to cook to about 5 to 10 degrees more after you take it out of the oven.
- If you are entertaining and want to ensure you have the perfect roast. Remove the lamb at about 135 F - this will be perfectly pink and about 140 F by the time you serve.
- Don't open the oven door too often to check doneness. Instead, calculate the cooking time and check closer to the time.
- Don't poke too many holes in the meat while checking for doneness. The moment you poke a hole in the meat you will see juices flow out. You want these to stay in so don't make too many holes. I poke the thermometer just once and leave it there until it reaches the desired temperature.
- Let the meat rest after cooking. If you cut the meat too soon all the juices will flow out of the meat and give you a dry roast. Instead, let the meat rest for at least 15 minutes if not more.
Cooking temperatures and time for lamb
I cook my lamb medium-rare, about 135 F using a meat thermometer. Here's a handy guide to use.- Medium rare - between 130 F to 135 F, approximately 20 minutes per pound.
- Medium - between 135 F to 140 F, approximately 22 to 23 minutes per pound.
- Medium well - between 145 F to 150 F, approximately 25 minutes per pound.
- Well Done is between 155 to 165 F, approximately 30 minutes per pound.
Nutrition Information
The nutrition information and metric conversion are calculated automatically. I cannot guarantee its accuracy. If this data is important to you please verify with your trusted nutrition calculator. Thank you
Natalie
My family loves roasted lamb. It's probably one of our favorite Sunday dinner options during the colder winter months. Your recipe sounds so delicious. I never used thyme for a lamb before. I will definitely give it a try next time I'm roasting a lamb.
Veena Azmanov
Thanks, Natalie. I hope you try it soon.
Nicole
I've never roasted a leg of lamb but your recipe and step by step instructions make it seem all very easy and approachable. Lamb and be intimidating (speaking from experience) but you may have convinced me to give it a try!
Veena Azmanov
I am so happy to hear that, Nicole. I hope you try. It really is easy. Thanks
Erin
Garlic butter marinade?! No way. I'm sold. Thanks for all the tips! I've never cooked lamb before so they're super useful.
Veena Azmanov
It is very easy Erin. You must try.
Andrea Howe
We love lamb but I've always been too intimidated to try roasting a whole leg of lamb. This gives me confidence.
Veena Azmanov
I am so happy to hear that. Thank you Andrea
Marisa F. Stewart
It doesn't seem like a celebration unless we have a delicious roasted leg of lamb. You give such great hints and it's exactly how we do it. You don't want to cook it until it's a scab - you have it cooked to at ideal temperature. And Lamb would not be lamb without rosemary. Great post.
Veena Azmanov
Thanks Marisa. Glad you liked it