Perfect Boneless Leg of Lamb Roast Recipe and Cooking Instructions:
What Size Boneless Leg of Lamb Roast to Buy
Boneless Leg of Lamb Roast Cooking Chart
Lamb Roast Internal Cooking Temperatures
Cooking Time Per Pound
Boneless Leg of Lamb Roast Recipe
Au Jus Recipe
Lamb is one of my favorite meats. I am particularly fond of boneless leg of lamb roast because it is so easy to cook and serve. To many families, lamb is traditional to serve for Easter Dinner, but it makes a great meal for any occasion. When cooked to medium rare, it is flavorful and mild so that anyone who enjoys roast beef will also enjoy this perfect leg of lamb roast.
What is Lamb Meat: Lamb is meat from sheep less than one (1) year old. If fresh local lamb is available, you will find no better. In the United States, fresh lamb is in season from March through October. If the phrase “Spring Lamb” is on a meat label, it means the lamb was produced between March and October, but lamb is available all the time. Frozen lamb is available year-round.
How to Select Lamb Meat: Look for a boneless leg of lamb roast with good marbling (white flecks of fat within the meat muscle), and meat that is fine textured and firm. In color, the meat on your boneless leg of lamb should be pink and the fat should be firm, white, and not too thick. Dark meat indicates an older animal. The USDA quality grades are reliable guides. Take lamb home immediately and refrigerate it at 40 degrees F. and use within 3 to 5 days, or freeze. It is safe to freeze lamb in its original packaging or repackage it. For best quality, use your boneless leg of lamb roast within 6 to 9 months.
What Size of Boneless Leg of Lamb Roast to Buy?
Boneless leg of lamb (with the bones removed) is perfect for oven roasting and is also very easy to carve. The term “boneless” means the leg bone has been removed from the lamb roast. A boned, rolled, and tied or netted leg is easy to roast. You can easily find this type of lamb at most large grocery stores or super markets.
For a generous serving of lamb roast, figure on 1/2 pound of lamb per serving. That means if you plan to serve:
six (6) people – 3 pound lamb roast
eight (8) people – 4 pound lamb roast
ten (10) people – 5 pound lamb roast
twelve (12) people – 6 pound lamb roast
for more than (12) people – purchase two (2) boneless lamb roasts
Cut the plastic outer wrapping off of the lamb roast, making sure that you do not cut through the netting surrounding the lamb. The netting holds the de-boned leg of lamb together and helps it keep it’s form. Do not remove the netting until after the lamb has been roasted. If you purchased your boneless lamb roast at a meat market or butcher shop, it may be hand-tied with string instead of the netting.
Boneless Leg of Lamb Roast Cooking Chart – How To Cook Lamb:
The chart below is only a guide. You must rely on an accurate Meat Thermometer and start taking temperatures half an hour before the end of the estimated roast time. Reminder: Instant read thermometers are not meant to be left in the roast during the cooking process.
What constitutes rare and medium-rare cooked meat? To satisfy government home economists, the Beef Council says rare beef means an internal temperature of 140 degrees F. Well, that is ok if you like well-done and dry meat. If you like moist, rosy meat (like I do), rare begins at 120 degrees and starts to become medium rare at 125 or 130 degrees. To cook your meat properly, you must purchase and use a good instant-read digital meat thermometer.
This is the type of cooking and meat thermometer that I prefer and use in my cooking. I get many readers asking what cooking/meat thermometer that I prefer and use in my cooking and baking. I, personally, use the Thermapen Thermometer shown in the photo on the right. To learn more about this excellent thermometer and to also purchase one (if you desire), just click on the underlined: Thermapen Thermometer.
Lamb Roast Internal Cooking Temperatures:
Rare:120 to 125 degrees F – center is bright red, pinkish toward the exterior portion
Medium Rare:130 to 135 degrees F – center is very pink, slightly brown toward the exterior portion
Medium:140 to 145 degrees F – center is light pink, outer portion is brown
Medium Well:150 to 155 degrees F – not pink
Well Done:160 degrees F and above – meat is uniformly brown throughout
Approximate Cooking Time Per Pound – Listed By Total Roast Weight
(Sear for 15 minutes in pre-heated 450 degree oven then adjust roasting temperature to 325 degrees F for remaining cooking time) – Remember to start checking internal temperature 1/2 before cooking time ends!
Cooking Multiple Lambs: If cooking more than one lamb roast in the same roasting pan, treat each lamb roast as individual roasts when determining cooking times. Use your cooking thermometer to check the internal temperature of EACH ROAST to determine the final internal temperature required to achieve the doneness you desire.
|Rare (120-125 degrees F)
|Medium-Rare (130-135 degrees F)
|Medium (140-145 degrees F)
|Well Done (160-165 degrees F)
|1 Hour and 15 minutes
|1 Hour and 30 minutes
|1 Hour and 20 minutes
|1 Hour and 40 minutes
|1 Hour and 15 minutes
|1 Hour and 40 minutes
|2 Hours and 5 minutes
|2 Hours and 30 minutes
|1 Hour and 30 minutes
|2 Hours and 30 minutes
- Leg of Lamb Roast, at room temperature (very important)
- If you really feel lazy, purchase some prepared pesto and rub over the surface of the lamb. You can also be creative and add additional herbs to your liking (such as mint, thyme, and/or oregano).
In a small bowl, combine garlic, rosemary, and pepper. Add olive oil and lemon juice. Mix until all ingredients are combined.
Remember - Do not remove the netting that is around the lamb roast.
Rub the Herb Seasoning Rub mixture all over the outside of the lamb.
Room Temperature: To cook evenly, the lamb roast must not be cold - let it stand at room temperature, loosely covered, for approximately 1 hour or even more. This time can vary depending on how big or small your lamb roast is. I can not give you an exact time on this. If you do not let the roast come to room temperature, it will take longer to cook your roast. Your roast will not cook evenly, and you will end up with well-done slices on the end and raw meat in the center. Use your best judgment!
Previously Frozen: If your boneless leg of lamb is frozen, let it thaw completely in the refrigerator. Remove the roast from the refrigerator about 2 to 4 hours before cooking to let it come to room temperature. Depending on the size of your roast, the time to come to room temperature may vary. I can not give you an exact time on this. Use your best judgment!
Preheat oven to 450 degrees F.
Pat the room-temperature boneless leg of lamb roast dry with paper towels or napkins. Using your hands, rub the outside of the lamb roast with olive oil or with the Herb Seasoning Rub (see above Herb Seasoning Rub).
Do NOT salt the outside of your lamb roast, as salt draws out moisture from the meat while cooking. You can use other seasonings or the Herb Seasoning, if desired, but I find it is not necessary. I know that some people do salt their meats before cooking, but trust me and do not salt - the result will be a juicy and delicious lamb roast to serve your family and guests!
Place the lamb roast on a roasting rack in a heavy stainless-steel pan or other metal roasting pan. NOTE: Select a roasting pan that has sides at least 3-inches deep. (I do not recommend using nonstick pans, as these pans yield fewer of the cooked-on bits that make the tasty au jus juice.)
Sear the lamb roast for 15 minutes at the higher oven temperature (450 degrees F.), then turn the oven to the lower temperature (325 degrees F.) for the rest of the cooking time. Do Not Cover the roast.
NOTE: If you ignore every other bit of advice I have given, please pay attention to this - For a perfectly cooked leg of lamb roast, invest in a good meat thermometer. Internal temperature, not time, is the best test for doneness and you don't want to blow this meal!
Insert meat thermometer so tip is in thickest part of lamb (not resting in fat). Cook until the lamb roast reaches an internal temperature of 120 degrees F. Remove from oven, cover with aluminum foil, and let sit approximately 15 to 20 minutes. Remember, the lamb roast will continue to cook as it sets. The temperature will rise to 125 degrees F. to 130 degrees F. internal temperature (medium rare) at 15 to 20 minutes. If allowed to rest as long as an hour, the temperature will rise even higher. So, pay attention to how long you let the cooked lamb roast sit.
About 1/2 hour before the estimated end of the roasting time, begin checking the internal temperature.
Place the cooked lamb roast on a large Meat Cutting Board with a well at one end to hold the juice.
Using your scissors, cut off the netting to remove and discard it. Using a sharp knife, slice the meat across the grain into whatever thickness you prefer. Sharpen your Carving Knife, if necessary using either a sharpening rod or stone.
Steel Sharpening Rod: To use a Steel Sharpening Rod or Steel, pull the edge down and across the rod, holding the carving knife at the same angle. Do this anywhere from 5 to 10 times.
Sharpening Stone (whetstones): To use a Sharpening Stone (whetstones), hold the carving knife at a 10 to 15-degree angle to the stone. Push back and forth in smooth, steady strokes.
Au Jus is aFrench term meaning "with juice." The term is used to describe the serving of meat, most often prime rib roast, but this technique works great with Leg of Lamb, surrounded in or served with a container of the natural juices that were produced as drippings while the meat was being cooked. It is not thick like a typical sauce or gravy.
While the cooked lamb roast is resting, now is the time to make a sauce from the drippings. Carefully spoon off any excess fat and discard. Scrape the bottom of the roasting pan to loosen the sediment. Pour the lamb juices (from the bottom of the roasting pan) into a saucepan. Add some red wine and some of the herbs (if used) that are left in the roasting pan.
IMPORTANT: Making Au Jus is more of a technique and not a recipe. You will have to do this by feel or guess work. It depends on how much juice is left in your pan (plus the juice from slicing the lamb roast), and how many people you will be serving.
Add the wine to the saucepan with the lamb juices and bring to a boil, and cook until the stock is slightly reduced, about 5 minutes. NOTE: Au jus is not thick like a typical sauce or gravy. Add the butter and mix it in by swirling the pan. Season to taste with salt and pepper. Transfer to a gravy boat.
Serve this sauce on the side when serving the sliced lamb roast. NOTE: Some chefs will strain the sauce before adding the butter (your choice).
* Add your wine according to how much Au Jus you think you will need for each person being served. I wish I could give you exact directions, but it is impossible to have an exact recipe for this. I usually use the same style of wine in the au jus that I will be serving at the dinner.
Comments From Readers:
Thank you so much for posting this article/recipe. I had never cooked or eaten lamb when I received a leg of lamb as a gift without cooking instructions. I found your article and followed the instructions and tips, resulting, in my opinion, in a wonderful meal that my husband thoroughly enjoyed. I will be using the leftovers to make a lamb stew. Again, thank you so much. I was terrified I was going to ruin it! – Cherie Jensen (3/26/16)
I, myself, do not care for lamb, but my husband does. When I made this for him using your beautifully, well-detailed recipe, his reaction was out of this world priceless! I thank you and will be looking forward to making many more of your masterpieces! Have a wonderful day! – Chanel Rose (1/9/15)