This boneless leg of lamb is is infused with fresh garlic and herbs and slow-roasted on a bed of vegetables.

Slow, oven-roasted leg of lamb is tender, easy to make, and serves a decent-sized crowd. This slow-roasted leg of lamb is made similar to slow-roasted lamb shanks in foil packets, however, everything is combined into one baking dish. If you'd like a beef version of this recipe, check out this Mediterranean pot roast.
Ingredient Notes
- Chopped vegetables: I use celery, carrots, potatoes, and onion, however, other vegetables can be substituted. I recommend fibrous vegetables with long cook times for this low and slow lamb roast recipe.
- Boneless leg of lamb: I use the boneless leg of lamb roast (from Costco) that's about 4 to 5 lbs (around 2.2 kg). Substitute a similar-sized bone-in leg of lamb for the boneless leg of lamb if desired.
How To Make Roasted Boneless Leg of Lamb
Set the oven to 325 ℉ (165 ℃). Peel and chop the carrots, potatoes, and onion. Wash and chop the carrots. Add chopped vegetables to the baking pan.
Marinate the lamb with mashed garlic, lemon juice, and a dried Italian herb blend. Place the lamb roast on top of the bed of vegetables. Add a layer of parchment paper and then tightly wrap with foil.
Bake at 325 ℉ (165 ℃) for 4 hours, completely covered the entire time with foil. After 4 hours, remove the parchment paper and foil from the oven and broil for 3 to 5 minutes until the top of the lamb crusts. Slice before serving.
Either serve the roasted boneless leg of lamb as is or prepare a lamb gravy using the leftover lamb drippings.
How To Make Lamb Gravy
Separate the lamb and vegetables from the juice. Pour the lamb drippings through a mesh strainer to remove any large chunks remaining.
In a small pot on the stovetop, add butter on medium-high heat. Once the butter is melted, add flour. Whisk the butter and flour together for about 30 seconds.
Add the strained lamb drippings, continuing to mix with a whisk. Remove from the heat once the lamb gravy thickens after about 1 minute.
Tips and Tricks
- Marinate the lamb ahead of time. Add the mashed garlic and lemon juice to the lamb about 2 to 4 hours prior to roasting.
- Don't use any fat. Lamb naturally contains a high fat content, so added butter or olive oil is not necessary.
- Chop the vegetables in large chunks. The vegetables cook for a long time, so larger size chunks hold up better.
Variations and Substitutions
Use a bone-in lamb leg. If you would prefer a bone-in lamb leg, use one! Just make sure the bone-in lamb leg is about the same size, so the temperature and cooking times will be the same.
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📋 Recipe
Slow Roasted Boneless Leg Of Lamb
Ingredients
Roasted Lamb
- 4 to 5 lbs boneless leg of lamb
- 5 large carrots
- 5 celery stalks
- 4 medium potatoes about 1.5 lbs (or ¾ kg)
- 1 large onion
- 8 garlic cloves mashed
- 1 lemon
- 1 tablespoon dried herbs
Lamb Gravy
- 1 cups lamb drippings
- 2 tablespoons of butter
- 2 tablespoons of flour
- salt to taste
Instructions
Make the Roasted Boneless Lamb Leg
- Peel and chop the carrots, potatoes, and onion. Wash and chop the celery. Add the chopped vegetables to a baking dish and add some salt and pepper.
- In a large bowl, marinate the lamb with mashed garlic, lemon juice, dried herbs, salt, and pepper. Keep the mesh string around the lamb (if present), and spread the seasoning all over the outside of the boneless leg of lamb.
- Place the marinated boneless leg of lamb on top of the chopped vegetables. Add a layer of parchment paper, then add a layer of foil. Tightly close the foil so that the baking dish is tightly covered. Bake the boneless lamb leg in the oven at 325 ℉ (165 ℃) for 4 hours.
- Remove the foil and parchment paper. Remove the mesh string. Set the oven to broil. Put the baking dish in the oven set to broil for about 2 to 4 minutes or until the top of the lamb is browned.
- Remove from the oven and serve as is. Alternatively, make a lamb gravy to serve with the slow-roasted boneless leg of lamb and vegetables.
Make the Lamb Gravy
- Separate the lamb drippings from the roasted lamb and vegetables. I just use a slotted spoon and carefully move over the lamb and vegetables to another dish. Then using a mesh strainer, I pour the lamb drippings to remove any large chunks. Set the lamb drippings aside.
- In a stovetop pot, melt the butter on high heat. Once the butter has melted, add the flour. Whisk for about 30 seconds until combined. Add the lamb drippings while continuing to whisk together until thickened (about 1 to 2 minutes). Serve the lamb gravy separately.
Notes
- Carve the boneless lamb roast just before serving so it doesn't dry out.
- Storage: Store the lamb and roasted vegetables in an airtight container in the fridge for up to 4 days.
Michelle H
Never having slow roasted a leg of lamb, I was concerned about the length of time it would be in the oven and if I would really be getting enough pan drippings for enough gravy-I was absolutely thrilled with the results. I made this using an already seasoned boneless leg of lamb (rosemary and garlic from Aldi), so I only had to drizzle some lemon juice over the top along with adding a fresh herb bundle of oregano and thyme. My lamb weighed just under 2.5lbs so I checked it after 2 hours and all told had it in the oven about 2.5hrs. I added a little finely diced cooked carrot and onion to the pan dripping gravy and it was delicious. This will definitely be my new favorite way to cook my boneless leg of lamb! Thank you, Lily, for putting this out there to be googled by home cooks like me who look for tasty ways to put dinner on the table:)
Lily
Thank you so much for the comment Michelle! I need to try the Aldi lamb leg.. its wonderful that it’s pre-seasoned. If you like lamb shanks- the lamb shank foil packet is great tender recipe too.
Stephanie
Tender and delicious!
Lily
Thanks for the comment!