Tender leg of lamb is just the thing for a cold winter’s day. Roasted with vegetables, herbs, and seasonings, it becomes impossibly moist, juicy, and flavorful. Serve this fall off the bone lamb with mashed potatoes for a world class dinner this Sunday (or any day)!
Cooking with lamb seems daunting, but it certainly doesn’t have to be. My slow roast leg of lamb recipe is fool-proof. With simple seasonings and ingredients, the hardest part is having to smell this delicious roast while it slowly cooks in the oven!
When I make this dish, I use a 5.5 lb bone-in leg of lamb as I feel the bone adds so much flavor. However, not every time I want this is one available! So, I have included instructions for both bone-in and boneless leg of lamb so that you can prepare this meal based on your favorite cut of meat — or whatever you are able to find in the grocery store. It is delicious either way!
There are two ways I prefer leg of lamb, too. One is where the outside is crusty and crisp and the interior is rosey pink OR the ultimate where it is exact opposite, fall-off-the-bone tender and smothered in gravy! l roast this about 40 minutes per pound or until the internal temperature registers 175°F. This can take about 5-6 hours or so.
Serve with Roasted Mashed Potatoes for a warm, buttery, creamy addition to your dinner. Some Roasted Vegetables would also make a great side, as would this Wild Rice Pilaf.
If you’re looking for a more intense lamb flavor, bone-in is the way to go.
Ingredient Notes and Substitutions
- Lamb – A protein with a strong, earthy flavor. Your cook time will vary depending on choice of cut and weight.
- Onion, Celery, and Carrots – When roasted with these vegetables, the meat soaks up all of their mildly sweet, earthy flavors. The aroma of all three cooking together is unmatched! Yellow or white onions will both work well in this dish.
- Orange – This fruit also contributes to the dish’s tantalizing aroma, helping to tenderize and add a degree of sweetness.
- Garlic – Have 15 to 20 cloves on standby for this dish. Due to its role in the pan gravy, I would not substitute this ingredient.
- Rosemary – Pairing beautifully with the meat, carrots, and orange, this herb has a complex flavor profile that matches well with citrus, sweet, and peppery notes. Thyme or sage could be used, if necessary.
- Beef Broth – We will roast the meat in a mixture of beef broth and water, helping it to moisten and tenderize.
- Flour – Use this to thicken the leftover juice from the roast, creating a mouthwatering pan gravy to serve with our dish.
How to Cook Boneless VS. Bone-In Leg of Lamb
- Boneless: Cook based on the weight of the meat. The netting should be left on to hold the de-boned pieces together. Leave the netting on a boneless cut of lamb until it is fully cooked, then cut it off with a pair of kitchen shears prior to carving. For a 4-7 lb cut, set your oven to 325°F. Adjust roasting times based on desired doneness:
- Medium Rare: Cook for 20 minutes per pound, with an internal temperature of 145°F.
- Medium: Cook for 25 minutes per pound, with an internal temperature of 160°F.
- Well-Done: Cook for 30 minutes per pound, with an internal temperature of 170°F.
- Fall off the Bone Tender Lamb: Cook 40 minutes per pound or until the internal temp registers 175°F. This can take about 5-6 hours or so.
- Bone-In: Again, adjust based on how many pounds of meat you’re cooking. Set your oven to 300°F.
- For a 4 to 4.5 lb cut, cover the pan and cook for 4.5 hours. Remove the cover and roast for 45 minutes longer to achieve a golden brown crust. If the meat is 6 to 6.5 lbs, roast covered for an additional hour.
Roast Bone In Leg of Lamb Recipe + Delicious Easy Garlic & Herb Marinade
FAQ
Is it better to cook leg of lamb with bone or boneless?
Does lamb cook better on the bone?
What is the best cut of leg of lamb?
Which cooking method is ideal for a leg of lamb?
Why is a bone-in leg of lamb better?
Moreover, a bone-in leg of lamb is actually easier to cook to pink, juicy perfection without the danger of overcooking and ending up with dry, tough meat. This is because of the way the bone acts an an insulator and helps conduct the heat.
Can I eat lamb instead of beef if I have high cholesterol?
Both lamb and beef have saturated fats and may raise the levels of bad cholesterol in the blood. Lamb generally contains more fat content when compared to beef or pork. Consumption of both lamb and beef should be in moderation.
Which is better bone in or boneless Lamb?
There are plenty of pros and cons for either. Bone-in can be more flavorful but trickier to slice and serve. It also takes longer to cook. Boneless does have a quicker roasting time and is easy to carve, but this cut might be more expensive. How long does it take to slow roast leg of lamb?
Should you buy a boneless leg of lamb?
If you are really nervous about carving meat, boneless is fine; it’s easier to slice. If you buy a boneless leg of lamb, it will probably come in a net. When the bone is removed from the lamb, the meat needs to be held together in the shape of the leg for cooking, so heatproof, oven-safe netting is usually used.