Roasted Leg of Lamb Recipe (video)

medium done roasted leg of lamb in casserole with baby potatoes

The most delicious, juiciest and aromatic recipe for roasted leg of lamb! My rosemary, thyme, mustard and garlic lamb is so easy to make and perfect for special occasions and holidays such as Easter. I roast the leg of lamb over a bed of baby potatoes, seasoning the potatoes as they bake. The aroma from this lamb roasting in the oven is mouthwatering! Enjoy this roast dinner for Easter, any special occasion or for Sunday roast dinner!

Watch My Roasted Lamb Video Tutorial

Watch my YouTube roasted leg of lamb video recipe for step-by-step instructions and watch me put together the lamb dish! Want to receive new recipe emails in your inbox? Make sure to subscribe to my website email list and my YouTube channel and turn on notifications!

Ingredients for Roasted Leg of Lamb

Here are the main ingredients you’ll need for this delicious roasted lamb recipe.

  • Leg of Lamb: use fresh, not frozen lamb for this recipe. More about what type of lamb next!
  • Garlic: for making the spread. I love to add lots of garlic for more flavor. It also helps mask any gamey flavor. 
  • Mustard: one of the best condiments for lamb meat. Mustard helps makes the lamb meat taste much less gamey. Use a medium to coarse ground mustard.
  • Rosemary & Thyme: fresh herbs work best for this recipe!
  • Olive Oil: for making the spread.
  • Kosher Salt: use kosher or coarse salt, or sea salt flakes. These types of salts penetrate better into the meat. 
  • Baby Potatoes: adding potatoes into the roasting pan makes this recipe a full dinner. Plus, the potatoes will taste so great after cooking in the lamb juices.

Bone-In or Boneless Lamb Meat

This roasted lamb recipe works well with both bone-in or boneless leg of lamb. There are pros and cons to either version but I personally prefer a boneless leg of lamb, even though it requires just a few extra minutes of prep.

You can add more seasoning, even on the inside, and it’s just as juicy as a bone-in leg.  If using boneless lamb, add the spread on the inside of the leg, where the bone has been removed.

Also, make sure to truss the meat using kitchen twine – this will ensure the meat cooks evenly. If you are using a bone-in leg, simply season the lamb with the spread all over.

roasted leg of lamb with dijon mustard and herbs

How to Make Roasted Leg of Lamb

You’ll love how easy this roasted leg of lamb is to prepare! Here’s how I make this dish!

  1. Start by preheating the oven to 350F/177C and place 2 to 3 pounds of baby potatoes into a large casserole dish. Season the potatoes with olive oil, salt, pepper and your favorite herbs. Toss to coat then set aside.
  2. Next, prepare the simple garlic and mustard spread. This spread is the perfect complement to lamb meat! It’s made with finely minced garlic, dijon mustard, thyme, rosemary, olive oil and salt and pepper. So easy to make and so flavorful!
  3. Before seasoning the leg of lamb with the spread, score the lamb fat that wraps around the meat. Scoring the meat gets the garlic and herbs deeper into the meat. Just make sure you don’t slice too far into the meat, which will allow precious juices to escape!
  4. Arrange the seasoned lamb over the potatoes. As the lamb roasts, it will release juices and fat, which will add even more flavor to the potatoes. Roast the dish uncovered until the internal temperature reaches 135F/57C, then rest the meat for 20 minutes before enjoying.
oven roasted lamb meat with potatoes and rosemary

Leg of Lamb Roasting Time

Roasting a leg of lamb can take 1 1/2 to 2 1/2 hours. The timing for this recipe depends on a few things: whether your lamb is bone-in or boneless and the size of the leg. The larger the leg, the longer it will take to roast.

  • Bone-in lamb will take slightly longer because the bone will affect the way the temperature distributes, but it will cook evenly.
  • Boneless lamb will cook slightly faster but it’s important to truss the meat for even cooking.  In my video recipe, I had a fairly large, boneless leg that I roasted for 2 hours.
  • Roast the lamb until a meat thermometer inserted into the thickest part of leg reads 135F/57C for medium doneness. For medium-well doneness, roast to 145F/63C.

More Recipes to Try!

Enjoyed this roast dinner recipe? Check out some of my other recipes you’re sure to enjoy!

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Roasted Leg of Lamb video recipe
medium done roasted leg of lamb in casserole with baby potatoes
5 from 7 votes

Roasted Leg of Lamb Recipe (video)

20 minutes prep + 1 hour 30 minutes cook
6 servings
Easy recipe for roasted leg of lamb with garlic, herbs and mustard spread with baby potatoes.


  • 1 bone-in or boneless leg of lamb
  • 2 tbsp dijon mustard
  • 1/4 cup olive oil
  • 1 tbsp fresh thyme
  • 1 1/2 tbsp chopped rosemary
  • 5 to 6 finely minced garlic cloves
  • 1 to 1 1/2 tbsp coarse Kosher salt
  • 1 tsp ground black pepper

For Potatoes:

  • 2 to 3 pounds baby potatoes
  • 1 tbsp olive oil
  • salt and black pepper
  • 1 tbsp herb blend – Italian or French


  • Preheat the oven to 350F. Place the potatoes into a large casserole dish or roasting pan. Drizzle with olive oil and season generously with salt, pepper and herbs. Use a spatula to toss the potatoes in the seasonings, until well coated.
  • In a small bowl, prepare the spread for the lamb: mix together the mustard, olive oil, thyme, rosemary, garlic, salt and pepper. Add more oil as needed until the sauce is creamy.
  • Next, prepare the lamb. Trim off any extra thick pieces of fat. Using a sharp knife, score the fatty layer that surrounds the leg of lamb, taking care not to go too deep. Watch mt video recipe to see how it’s done. Using your hands, rub the prepared spread all over the leg of lamb, making sure the meat is well seasoned all over. If using boneless leg of lamb, season the inside of the leg where the bone as been removed.
  • If using boneless leg of lamb, season the meat all over, then use kitchen twine to truss the meat; the leg meat should be snugly together. Trussing the meat will ensure it cooks more evenly. Watch my video to see how it’s done.
  • Arrange the leg of lamb over the seasoned potatoes. Roast uncovered in the preheated oven at 350F/177C for 1 1/2 to 2 1/2 hours, until the internal temperature reaches 135F/57C for medium doneness. For medium-well, roast the lamb to 145F/63C. Bone-in lamb will take slightly longer. Timing also depends on size of the leg. Once the meat is done, allow it to rest in the casserole pan for 15 to 20 minutes before slicing using a sharp carving knife. Make sure to remove any kitchen twine before slicing!


Calories: 534kcal | Carbohydrates: 29g | Protein: 53g | Fat: 23g | Saturated Fat: 6g | Polyunsaturated Fat: 2g | Monounsaturated Fat: 13g | Cholesterol: 152mg | Sodium: 2346mg | Potassium: 1369mg | Fiber: 4g | Sugar: 1g | Vitamin A: 94IU | Vitamin C: 33mg | Calcium: 67mg | Iron: 6mg