I love a good roast lamb (proof). Here’s my classic recipe for lamb leg, rubbed with garlic and rosemary, served with gravy, peas, carrots and crispy roast potatoes (duck fat or classic). I hope you love it as much as I do!
The only thing you need to know for perfect roast lamb leg
I have a lot to say about roasting any kind of meat. Especially Australia’s favourite roast – the great lamb leg. But there’s really only one thing you need to know to make perfect roast lamb leg, every single time:
GET A MEAT THERMOMETER!!
It’s the only way you can take the guesswork out of cooking lamb leg so it’s perfect blushing pink and ridiculously juicy inside. Because – and here’s something Aussies don’t like to talk about – lamb leg is actually very lean so if it’s not pink, it’s dry. Full stop, end of story!
My meat thermometer – For most of my adult life, I was using a $5 thermometer I got on Ebay which never failed me. A few years ago I finally decided it was time to invest in a real one so I got a Thermapen which is pretty well regarded as the best (my thoughts here). Even if you can’t invest in a Thermapen – it’s the 21st century, and even cheap tech isn’t so bad. Invest in a $5 meat thermometer. That’s a lot cheaper than a wasted, overcooked lamb leg!
OK, I do have a few more “how to make the perfect roast lamb leg” tips!
Garlic rosemary rub – classic lamb flavours.
Start on high to get the colour going then lower heat.
Roast on a bed of garlic (or onion).
Make the gravy using the pan drippings. Roast lamb gravy is better than every other cut of meat – beef, chicken, pork, none of them compare!
What you need for roast lamb leg
Starting with the hero ingredient – the lamb leg! Get the best you can afford – yes, meat is like wine, the more you pay, the better the quality. Quality of life of the animal also comes into play there.
All that red ink you see is perfectly safe to eat and actually, you only see it on better quality lamb. You don’t typically see it on supermarket lamb.
Cut bone – Some (most?) butchers and almost all supermarkets sell lamb leg with the shank (bone) cut. Either fully cut off or partially cut so it folds. This is simply for practical reasons – shelf storage and packing space. For grandness, I like the bone in tact. But it doesn’t matter ,it’s purely a visual decision!
Rub for roast lamb leg
Here’s what you need for the rub: rosemary, garlic, olive oil, salt and pepper. Use fresh rosemary – dried is not the same!
Roast lamb gravy
All you need for gravy is flour for thickening and beef stock/broth for the liquid. You shouldn’t need extra salt for the gravy. I find the salt on the lamb that ends up in the pan drippings plus the salt in the beef stock is enough. But taste and add more if you want!
Why beef rather than lamb stock? Well, there’s a reason lamb stock is not typically sold at grocery stores! It’s just very…lamby. 🙂 Beef has a cleaner flavour. It doesn’t make the gravy taste beefy at all because there is so much lamb flavour from the drippings.
Why not chicken stock? It works fine but the gravy colour is paler. I like my gravy for roast lamb leg to be a really deep brown colour!
How to make roast lamb leg
Rub with rosemary and garlic, roast in a hot oven to get the colour going then continue at a lower temperature for 1 hour or until the internal temperature is 53°C/127°F (for blushing pink perfection). Rest for 20 minutes before carving. It will still be very warm even after 1 hour – enough time to make duck fat potatoes!
The lamb leg pictured is a 2.75 kg lamb leg which is about the average size you get from good butchers. Supermarket lamb legs tend to be a little larger from slightly older animals which makes the meat a little less tender and a little stronger “lamby” flavour. Albeit, as you’d expect, cheaper than from butchers.
Make rub – Mix oil, garlic and rosemary in a bowl.
Rub then sprinkle – Slather the rub all over the lamb, then sprinkle the salt and pepper all over. It’s better to do it this way for more even dispersion of salt – if you put it in the oil, it doesn’t spread quite as evenly because it pools in the bottom of the bowl.
I do this rubbing step in the roasting pan – why dirty a cutting board??
Garlic bed – Place cut garlic and rosemary under the lamb.
Hot oven 20 minutes – Roast for 20 minutes in a hot 240°C/475°F (220°C fan) oven. This will get the colour going on the lamb. It’s tempting to go longer to get even more colour on it but I find if you go beyond 20 minutes you end up with too much overcooked meat “ring” on the outer edges of the lamb.
1 hour lower oven – Reduce heat to 200°C / 400°F (180°C fan) and roast for a further 1 hour or until the internal temperature of the lamb is 53°C/127°F for blushing pink perfection.
Check the internal temperature at the 45 minute mark. Never rely on a recipe cook time for roast meat, use your thermometer! So many variables can affect the exact roasting time, from oven strength to pan heat distribution, the shape of the lamb leg and how cold the meat is right in the middle.
See below for more information on lamb doneness and different size lambs.
Rest 20 minutes – Rest the lamb for 20 minutes before carving. During this resting stage, the lamb finishes cooking and the internal temperature will rise to 62°C/144°F which is perfect medium rare for lamb.
Also during resting, the lamb juices get re-absorbed by the meat fibres so when you cut into the meat, the juices remain in the meat and eventually end up in your mouth. If you do not rest the meat then the meat juices leak out everywhere when you start carving the lamb.
Internal temperature of roast lamb leg
No credible restaurant would ever serve lamb leg at anything over than medium rare! But I do know some people like their lamb done a little more, so here are the internal temperatures for lamb leg at different levels of doneness.
Take the lamb out when it hits the “temperature out of oven”. After resting for 20 minutes it will rise to your target level of doneness.
TIP: Take the lamb out early!!!
This is one of the most common mistakes people make when roasting lamb. If you want medium rare lamb and you take the lamb leg out of the oven when it hits 62°C/144°F (which is the medium rare target temperature), it will rise to 73°C/163°F once rested which is well done – no hint of pink at all! This occurs because the lamb continues to cook after you take it out of the oven due to residual heat. It’s called carry-over cooking.
So if you want medium rare, perfectly pink lamb leg, you need to take it out of the oven once the internal temperature reaches 53°C/127°F. At this temperature, the lamb is rare.
But when you rest the lamb for 20 minutes, it will continue to cook and the internal temperature will rise by 9°C/17°F to 62°C/144°F. This temperature is medium rare, the optimum doneness for lamb leg so it’s beautifully juicy. Any more and the lamb meat is drier than ideal, because lamb leg is a lean meat.
How to make gravy for roast lamb leg
Gravy for lamb leg is made using the pan drippings after roasting the lamb. “Drippings” simply refers to the fat and meat juices left in the roasting pan after roasting the meat and it’s our express, free path to a killer gravy.
Heat drippings & cook flour – Once you take the lamb out of the roasting pan, put it straight on the stove to heat the fat. Add flour and stir it for 1 minute to cook it off – it will kind of be like a paste.
Pour in the beef stock, stirring as you go to help dissolve the flour.
Smush the garlic with a potato masher or even a smooth to help release the beautiful caramelised garlic flesh into the gravy.
Strain – Then just simmer for a few minutes until the gravy thickens to your taste then strain into a bowl, pressing the gravy liquid out of the garlic heads. Then pour into a jug to serve!
And that, my friends, is everything you need to know to be the king (or queen) of roast lamb leg from this day forth. The precision by which you roast your lamb to blushing pink perfection will be admired. Your gravy will be whispered about in your circles – the flavour!!! It’s incredible!
Just smile sedately, sit back and bask in the praise. There is no need to reveal your recipe source. 😎
The lamb leg in this post is pictured with duck fat potatoes (the best crispy potatoes in the world!) with peas and steamed carrots tossed with a little butter and parsley. If you don’t have duck fat, make my classic crunchy roast potatoes instead. They are still way crunchier than your usual way of making them.
Go forth and enjoy your new lamb-alicious world! If you’ve got your own lamb leg secrets, sharing in the comments below – readers love hearing what you have to say. – Nagi x
Watch how to make it
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Roast Lamb Leg with Gravy
Ingredients
- 2.75 – 3 kg / 5.5 – 6 lb lamb leg , bone-in (Note 1)
- 1 1/2 tsp cooking salt
- 1/2 tsp black pepper
Rub
- 1 1/2 tbsp fresh rosemary leaves , finely chopped
- 3 garlic cloves , finely minced
- 2 tbsp olive oil
Base
- 2 whole heads of garlic , halved horizontally (Note 2)
- Few sprigs rosemary (optional)
Gravy
- 4 tbsp flour , plain/all purpose
- 2 1/2 cups beef broth / stock , low sodium (Note 3)
Instructions
- Take lamb out of fridge at least 1 hour before roasting. (Note 4)
- Preheat oven to 240°C/475°F (220°C fan) with oven shelf in the middle.
- Rub – Mix rosemary, garlic and olive oil.
- Prepare lamb – Place lamb leg in a roasting pan. Coat with the rub using your hands, the sprinkle with the salt and pepper. Place garlic and rosemary sprigs underneath the lamb, garlic cut face up.
- Roast lamb leg for 20 minutes. Turn the oven down to 200°C/400°F (180°C fan) and roast for a further 1 hour or until the internal temperature reaches 53°C/127°F for medium rare (Note 5 other doneness). Check first at 45 minutes – everyone's oven is different!
- Rest – Remove lamb from oven. Transfer lamb to plate, loosely cover with foil and rest for 20 minutes to 1 hour (it will still be warm enough for serving!). The internal temperature will rise to 62°C/144°F (medium rare). Make gravy while lamb is resting – below.
- Serve lamb with gravy, duck fat or classic crunchy roast potatoes, peas and steamed carrots tossed with butter and parsley.
Gravy for roast lamb leg
- Drippings in pan – Discard rosemary sprigs. You should have around 4 – 5 tbsp of fat (drippings). If less, add butter. If much more, discard a bit.
- Add flour – Place roasting pan on stove over medium heat. When the fat starts to bubble, then add flour. Mix flour in and cook for 1 minute.
- Stock – Pour in half the beef stock and mix to dissolve sludge in, then add remaining beef stock and mix.
- Garlic squidging – Use a potato masher (if you're really keen like me) to mush the garlic to squeeze out the flavour (also helps flour caught in garlic to dissolve).
- Taste – Check salt and pepper (I don't add more).
- Thicken – Simmer for a couple of minutes, stirring, until it starts to thicken. Take it off the stove BEFORE the gravy is the thickness you want because it will keep thickening.
- Strain into a bowl, mushing garlic to squeeze all the liquid out. Then pour into gravy jug and serve with lamb!
Recipe Notes:
1. Lamb leg – Recipe is based on a whole lamb leg. See roasting time table above for different lamb sizes. Sometimes the bone sticking out is removed, sometimes it is partially cut so it folds inwards. It doesn’t matter either way, but just ensure the bone inside the meat is not removed. (If it is, you have a butterflied lamb leg – use this recipe instead).
Boneless lamb – I love making Greek butterflied lamb leg. If yours is rolled and tied, you could make this recipe but the meat is not quite as juicy because it’s been cut to remove the bone so there’s more escape roots for meat juices! If you can, unroll the lamb to do the rub then roll it back up and tie again (excellent flavour infusion!). Also, cook time likely a bit shorter. I’d do the 20 minute high temp blast, lower oven then check at 40 minute mark.
2. Garlic base – Elevates the lamb slightly so it cooks more evenly and allows the fat to drip over the garlic so the flavour infuses into the drippings that then forms the base of the gravy. Place garlic cut side up so the flavour infuses into the flesh of the lamb.
It is not garlicky at all because when garlic roasts, it becomes sweet and caramelised. It is my big secret for making a killer gravy for roast lamb! You can use 1 onion, quarters (skin on) instead of or in addition to garlic.
3. Gravy for lamb is best made with beef stock/broth because it has a deeper flavour and makes the gravy a beautiful dark brown colour. Store bought is fine, though homemade makes it ultra restaurant-worthy! If you cannot consume beef for religious or health reasons, then chicken broth can be substituted.
4. De-chilling lamb will make it cook more evenly. Cold lamb leg = overcooked on the outside by the time the inside is cooked.
5. Internal temperature of cooked lamb leg:
I highly recommend getting a meat thermometer for accuracy – only guaranteed way to get juicy lamb every time!
6. Holding – The lamb leg will stay warm for up to 1 hour, enough time to make duck fat or classic crunchy roast potatoes! The inside of the lamb is still warm even after 3 hours.
7. Servings: A 2.5 kg/5 lb lamb serves 6 very generously and 8 comfortably. After taking into account the bone (500g/1lb) and meat juices lost during roasting, you should end up with around 1.7kg meat after cooking which is around 280g for 6 people (generous!) or 200g for 8 people. If you slice lamb thinly it will go further!
8. Nutrition per serving, assuming 8 servings and that all the gravy is consumed.Nutrition Information:
Originally published October 2016. I have been very neglectful not updating one of my favourite recipes with sparkling new photos and a recipe video!
I told you – I LOVE roast lamb! See?
Life of Dozer
Original photo from when I first published this recipe in 2016 still holds true, so no need to update:
DOZER. Don’t breathe your stinky dog breath over my friends while they eat!
Savory depth to flavor, Super tender. Will be making many times! Thank you!
Hi Nagi, my partner has been using your recipes for some time and I wanted to cook her a special lamb roast as a surprise. Your recipe did not disappoint. The meat was perfectly cooked due to your wonderful instructions. Thank you
Hi Nagi, how are you? I have been tasked to make a lamb roast this weekend and we could only get hold of leg of mutton, it is fresh and organic. Would the cooking be different for this? Or can I follow your recipe as is? Thank you
How do you get potatoes so brown
Oops…sorry Nagi….blame my typing !!
Magi, aussie expat here ,living in the US….Italian in spirit…so cooking is in my DNA ! I have cooked land all my adult life….only selected N.Z. or Australian lamb….have fed lamb across the US from the Deep South to the California desert. So many Americans dislike lamb, BUT once they have tasted “our” lamb they are converts. I have introduced your recipe to my lamb recipes, and now use your recipe almost exclusively. It is a winner. Thank you.
I can’t tolerate garlic…can you suggest other herbs for flavor on the lamb? TYIA
Yes!! I usually murder meat but having invested in a meat thermometer, carefully reading the cooking times posted at the end of the recipe ( very helpful, thank you!), adding finely grated lemon rind to the rub and doubling the quantities – I JUST MADE DELICIOUS MID WEEK ROAST LAMB!! Unbelievable. Brilliant work Nagi, Love your recipes, thank you!!
Winter Greetings from Cairns Nagi,
Mid afternoon here and a chilly 24 degrees .. Time to put the Greek Style Slow Cooked Lamb in the oven to give the Boss Lady and a couple of friends a cool evening treat!
Thank you .. You’re my ‘Go To”
best recipe girl!
Charles.
Nagi, for years since Mum passed I have been trying to recreate even a small comparable to her Sunday lamb roasts for myself and my father.
Numerous times I tried and numerous times it just didn’t compare.
I found your recipe here and I have to say it’s as close as I have gotten it!!
I can’t thank you enough…
A few tweaks to refine it towards my oven and cooking style etc but near perfect already!!
THANK YOU!!
Oh that’s lovely to hear Gareth!!! ❤️❤️❤️ N x
Hi Nagi, Another fabulous recipe, I used carrots also to give the height as only had one head of garlic but still squidged/sieved for the gravy. It was delicious. I like your cooking time instructions, always perfect. Thanks.
Made this today was lovely what can I make with leftovers
Many thanks
Gillian
Hi Gillian, you can slice ti up and use it in kebabs – one of my favourite ways to use up left over lamb! N x
Be Italian, we would use a boning knife to pierce the leg of lamb & place a half clove of garlic (sliced lengthwise) in the in resulting space. We would repeat this 10 times or so all over the leg of lamb. As a teenager, that was my job. It gave a lovely galic flavor to the meat.
I’ve always thought of roasting a leg of lamb as being some mysterious process reserved for the elite chef class! Following your detailed instructions, I made this two nights ago, and the results were delicious, and it was also quite simple. It was so yummy that my friends asked me to do it again tonight for a birthday party! I didn’t really change anything, except I added some mustard powder and Thyme to the rub, and included carrots with the potatoes for the roasted veggies. I always enjoy your recipes. I find them to be detailed and simple, but most of all, always tasty! Thanks.
6.75lb leg of lamb want to roast
want to cook a 6.75lb whole leg with bone the oven settings in f
The lamb and gravy taste so good! Lamb is juicy and not overcooked, thanks to the cooking times guide.
I love all your recipes. They are so detailed yet easy to follow. Great for a novice cook like me.
I don’t understand how people think roasting lamb & other meats is so difficult. The way you explain everything makes the job so enjoyable, easy to cook and absolutely delish.
I don’t use an internal thermometer but rely on the timings you provide and it was perfect. A beautiful blushing pink.
Loved the gravy with the hint of garlic running through.
Good on ya Nagi.
Hi Nagi, I am planning this for my Christmas dinner. Unfortunately the smallest leg of lamb I was able to find was 9lbs! How should I adjust the cooking time for medium cooked – 2 hours? I will also double the quantity of the ingredients. Thanks so much!!!
Is that a lamb leg – are you sure?! 😂 You’re probably going to be roasting for 2 – 2hours 20, definitely make sure you have a meat thermometer on hand to check the temps to get the desired done-ness as per the notes.
Hi Nagi. I’m planning to do this for Christmas. Do we need to trim the fat before roasting? Pros and Cons if any bout fat trimming please. Thanks again for the lovely recipe and video
Hi Nagi, as always love your recipes really flavorful. I thought you might get a laugh out of this, when I see your picture at the top of the page I caught myself saying hellllo Nagi. So as I use a lot of your recipes for the flavour, just know you are getting lots of hello’s in this covid season from a. Irish person living in Canada. Once again thank you for the recipes. Caroline