This Slow Roast Leg of Lamb is going to take your next Sunday roast to a whole new level! It’s ULTRA EASY and very forgiving. It does take patience as it takes 4 1/2 hours in the oven, but you’ll be rewarded with lamb leg that’s fall-apart tender with an incredible rosemary garlic infused gravy.
After more roast lamb ideas? Browse all my roast lamb recipes or take the Roast Lamb Matchmaker here which will lead you to your perfect recipe!
Slow Roast Leg of Lamb
I’ve said it before and I’ll say it again – lamb leg should either be roasted exactly such that it’s blushing pink inside – either whole or butterflied – or long and slow so it’s ultra tender.
Blushing pink = meat thermometer or holding-your-breath-cross-your-fingers for that moment when you carve, hoping for juicy lamb rather than grey and dry. If that’s what you’re after, use this classic Whole Roast Lamb Leg recipe or my Greek Butterflied Leg of Lamb for a quicker boneless version – and yes, you really need a meat thermometer.
This recipe is for the other way – long and slow, the sort of meat you pull off the bone with tongs. It’s much easier, less stressful, and you don’t need a thermometer.
And it’s Amazing. With a capital A!
💕 Finding your perfect Roast Lamb recipe! 💕
Not that I want to deter you from using this recipe, but just so you know, I have shared quite a few roast lamb recipes over the years. Because – lamb! How I love thee!
I know it can be hard to choose with so many options so I made a fun (but genuinely useful) Roast Lamb Matchmaker to guide you based on effort level, budget, make-ahead needs, and even cuisines. Because did you know a roasted lamb shoulder reheats 100% perfectly whereas lamb leg is leaner so best served freshly made, even if it’s slow-cooked? 🙂
Take the Roast Lamb Matchmaker here to find your perfect lamb recipe!
How to make a Slow Roasted Leg of Lamb
All the lamb needs is a sprinkle of salt and pepper, drizzle of olive oil, then beef stock/broth and water in the pan which keeps everything all nice and moist + makes pan juices for gravy, cover then slow roast for 5 hours until tender and fall apart.
For an incredible hands-off version of this slow roast leg of lamb, try the Slow Cooker Roast Lamb!
Roasting bed – Put garlic, onion and rosemary in the roasting pan. This is the bed on which the lamb is roasted and it serves three purposes:
1) to keep the lamb elevated out of the pan juices for even cooking;
2) flavour the flesh that’s in contact with it; and
3) flavours the pan juices which is used to make the gravy.Season – Sprinkle the lamb leg all over with salt and pepper. In this photo, the lamb leg is the right side up which is covered with a thin layer of fat.
Upside down – Turn the lamb upside down and pour the liquids around it. Lamb leg is quite lean so it benefits from slow-cooking submerged in liquid which helps keep the meat moist. If you roast it like a regular lamb leg (right side up, exposes, no foil cover), the meat would end up terribly dry.
Drizzle the surface with oil (just the exposed surface, no need to turn the lamb over).
Slow roast – Roast for 4 1/2 hours at 170°C/325°F (150°C fan-forced) or until the meat on the underside that was submerged in the liquids can be easily pried apart using two forks.
Brown – Turn the lamb over then roast uncovered for 20 to 30 minutes or until it’s nicely browned all over.
The lamb is now ready! But it’s important to rest it for at least 15 minutes before serving which will allow the juices in the meat to redistribute throughout the meat fibres (makes the meat juicier). So transfer it to a platter and loosely cover with foil to rest while you make the gravy.
💡 USEFUL TO KNOW
The lamb will stay warm for 1 1/2 hours so you don’t need to rush the gravy, or worry about rushing to serve it freshly made.
Large roasts usually rest longer (30+ minutes), but because this one is slow-cooked to fall-apart tenderness rather than carved, it needs much less resting time.
How to make the gravy for slow-roasted meat
A great gravy comes down to the flavour in the pan juices and this one knocks it out of the park! All the tasty lamb roasting juices plus the garlic, onion and rosemary is what makes this gravy so good. Here’s how to make it – it’s a cinch!
Heat – Set the pan on the stove with all the liquid that it’s in it, including the garlic and onion which will look like a mushy sludge by now but adds a stack of great flavour into our gravy. Turn the stove on to heat the pan juices then scatter the flour over and mix it in.
Whisk in water then simmer until it becomes a gravy consistency.
Strain into a bowl, pressing all the tasty sludge out of the garlic and onion. (I really need to think of a better word that “sludge” 😆)
Pour into a gravy jug and it’s ready to use!
💡 USEFUL TO KNOW
Leftover gravy keeps in the fridge for 4 days or freezer for 3 months. Use for sausages, peas, chicken, or dress up your mash!
To make it gluten free, just skip the flour and use a cornflour slurry instead. Directions in the recipe card.
Sides to serve with roast lamb
Complete your meal! Here are a few suggestions for sides that go really well with roast lamb:
I promised this was easy, and I meant it. It’s forgiving because if the meat’s not tender enough, you can just stick it back in the oven until it is – and you can cook for even an hour beyond necessary and it’s still going to be juicy.
If the gravy gets too thick, no dramas, just add a splash of water. If the gravy is lumpy, no worries, because in this recipe, it’s strained.
In short – it’s pretty hard to stuff up. If you’re a roast lamb first-timer, just give yourself a couple of extra hours because this lamb reheats great in the microwave or oven, as does the gravy.
Sunday night roast is never going to be the same again! – Nagi x
Just before you go!
Saturday 11 April 2020 – That you are here, looking at this roast lamb recipe for Easter 2020 fills my heart with happiness because it says that you are in some way able to hold onto Easter traditions, despite being stuck at home and unable to celebrate with extended family.
But for many healthcare workers around the world, including my hometown of Sydney, they will be working too hard to celebrate Easter. These brave men and women who are literally risking their lives to save ours.
I feel morally obliged to do something, so I am running a program where you can buy a meal from a local business for our overworked Frontliners. Too exhausted to cook, many are turning to fast food and those who try to cook are faced with empty supermarket shelves.
If you would like to Shout A Meal for a Sydney Frontliner to express your thanks, please click here for my fundraiser and here is more information about my program “Shout A Meal”.
Thank you for reading, and Happy Easter! – Nagi x
Watch how to make it
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Slow Roast Leg of Lamb
Ingredients
- 2.25 kg / 4.5 lb leg of lamb , bone in (or shoulder) (Note 1)
- 1 1/2 tsp cooking salt / kosher salt (double for flakes)
- 1/2 tsp black pepper
- 1 1/2 tbsp olive oil
- 1 whole garlic head , unpeeled, cut in half horizontally
- 1 onion , quartered (unpeeled is fine)
- 2 rosemary sprigs (2 = whisper of rosemary flavour, 4 sprigs = stronger flavour)
- 3 cups beef stock/broth , low sodium (or homemade)
- 2 cups water
Gravy:
- 4 tbsp plain flour (all-purpose flour)
- 1 cup water
- Salt and pepper , to taste
Instructions
ABBREVIATED
- Season leg with salt and pepper, place upside down on garlic, onion and rosemary. Pour liquids in, drizzle with oil, cover with foil. Roast 4 1/2 hours at 170°C/335°F (150°C fan) until meat is pull-apart tender. Flip, return to oven 20 – 30 minutes at 200°C/390°F (180° fan) until well browned. Make gravy while resting.
FULL RECIPE
- Preheat oven to 170°C/335°F (150°C fan-forced).
- Place garlic, onion and rosemary in a metal roasting pan.
- Season lamb: Place lamb leg right side up in the pan. (Note 2) Sprinkle the surface with half the salt and pepper and rub it in.
- Turn lamb over and place it so it mostly sits on the garlic and onion. Sprinkle with remaining salt and pepper, rub it in. (Video helpful here)
- Add liquids and cover: Drizzle lamb with olive oil. Pour broth and water around the lamb – it won't cover it, that's ok, the lamb sinks into it. Cover with foil (don't use a lid, you want a bit of liquid to steam out).
- Slow roast: Place in the oven and roast for 4 1/2 hours. (See Notes for roasting time table)
- Check meat: Remove from the oven, remove foil. Turn lamb over. Check it to ensure the meat is tender enough to pry a bit off easily with a fork. If not, return, covered, to oven.
- Brown lamb: Return uncovered lamb to the oven and roast for a further 40 minutes or until well browned all over. (Don't increase the temperature as then it doesn't brown as evenly)
- Rest: Remove lamb, spoon over pan juices generously. Transfer to serving platter, cover loosely with foil while you make the gravy (stays warm for 1 – 1 1/2 hours).
Gravy:
- Skim fat: Use a large spoon to skim off and discard some of the fat from the surface of the liquid.
- Add flour: Place pan on the stove on medium high. When the liquid bubbles, add flour. Use a whisk to mix it in – this may take a few minutes as the liquid reduces.
- Add water: Once it looks like sludge (see video), whisk in 1/2 – 1 cup of water until it becomes a gravy consistency to your taste. Adjust salt and pepper to taste – I rarely add extra salt.
- Strain gravy into a bowl, pressing juices out of the onion etc. Pour gravy into jug.
Serving:
- The meat is tender so you will only need tongs to tear the meat off. Serve with gravy!
Recipe Notes:
6. Gluten-free gravy – Skip the flour. Mix 2 1/2 tbsp cornflour/cornstarch with 3 tbsp water and use in place of the flour.
Servings – Allow ~350g/12 oz uncooked bone-in meat weight per person, so a 2.25kg /4.5 pound leg will serve ~6 people. I know this sounds like a lot of meat per person, but you lose more weight with slow cooked meats than roasting leg to blushing pink. plus the bone is sizeable and nobody can carve every scrap of meat off the bone. 🙂
Make-ahead – This is best served freshly made as leg is quite lean so it just isn’t as succulent when reheated. It stays warm for 1 hour so you needn’t worry about being 100% precise with cook timing. Leftovers will keep for 3 to 4 days in the fridge, or freezer for 3 months.
Nutrition per serving assuming 10 servings.
Nutrition – Calories in the nutrition are higher than actual because I do not know how to adjust for the fat that is skimmed off the liquid before making the gravy. I usually throw out about 1/3 cup which means the calories is probably closer to 500 calories per serving, and that’s assuming all the gravy is consumed.Nutrition Information:
Originally published May 2017. Updated for housekeeping matters April 2020 and 2026 – no change to recipe!
More Roast Lamb Recipes
I love a good roast lamb – so I’ve shared a few over the years! Here are some of my favourites – or browse the whole recipe collection.
Best of Sunday Supper Roasts
Life of Dozer
The time I had ambitions for him to be the next Kleenex puppy…
Seriously the best lamb ever! Even my husband who is anti gravy/sauce loves it!
Cooked this on St David’s Day here in the UK and used our wonderful Welsh Lamb. It was magnificent! I served it with your Dauphinoise Potato recipe which was also fabulous! Thank you Nagi for the recipes!
We Aussies love our lamb! I experimented with a small piece of lamb leg (only about 700g or a 1lb) for this recipe to see what it was like – wish I’d made more! It was fork tender and really took on the flavor of the rosemary and garlic. I’m definitely making it again, and soon! Thank you.
This is a an easy to follow recipe and worth the wait cooking it for 5 hours.
It’s St Davids Day here in the UK so it had to be Welsh Lamb Delicious! 5*****
So easy! It’s the nicest lamb I’ve ever had. Fall off the bone perfection and the gravy tastes great too!
This is a brilliant recipe. Just cooked it for valentines day along with your roast potatoes. Thank you nagi!
I’ve cooked my lamb leg just like the recipe states several times and it really was fantastic. I have to say there are quite a few recipes I’ve made from Nagi and they are all fantastic!! Well done in this day and age where anyone can create a blog with recipes online and its then left to us, the audience to sift through to find good ones. Recipetineats is definitely a keeper, much respect 💜💜💜
Excellent, tender, when coated in the gravy it’s very indulgent. The best way to roast lamb, thanks Nagi!
Lamb is a tradition on Australia Day – this just became a family tradition. I knew when the bone fell out that it was going to be delicious. My golden retriever loved it too!!!
I’m so glad you enjoyed it Mel, I hope you had a great Australia Day! N x
Made this with a half leg of lamb for our anniversary diner. Cooked at 140°c for 4 hours. Added some red wine to the gravy. So easy to make and it was just delicious!
WOOT! You nailed it Roy! N x
Please can I check – was this 140 in a fan assisted oven? And does the 4 hours include the browning time? I have a 1.2kg half leg of lamb to cook tomorrow – thank you!
I made this using a whole leg before Christmas and it was amazing! I froze half away in the gravy and we reheated it for a dinner over New year. I have made it again today using two half legs. Amazing again! Thank you so much for this recipe! I have emailed the link to your page to my family and friends!
Hi! I have a 1.1 kg leg, any idea on time needed to cook?
We made this today and it was more than amazing, My family said it was the BEST roast lamb they had ever eaten – much to the chagrin of my husband who usually cooks the roasts. Truly a thing of exquisite beauty Thanks so much Nagi!
Wahoo, sounds like you nailed it Amanda!!! N x
Just made and served this for my brothers Birthday dinner and it was a HUGE hit. I’ve always just roasted leg of lamb and will never do that again as this is the best lamb I’ve ever served. Followed the recipe to a ‘T’ and it was a slam dunk. Thanks for every recipe of yours I’ve ever tried as every one has been a success.
Awesome Deeann – it’s hard to go back to a traditional roast once you’ve had slow cooked! N x
Unfortunately have tried this twice and it’s always coming out tough. I’m cooking it low and slow with foil. The always seems to be a fair bit of liquid. Would cooking it longer change this toughness? Wondering if the meat should be submerged more?
We have success with most of your other recipes
Hi Tahli – yes, you need to cook it longer. When cooking leg, it goes from raw to pink & juicy (which is the classic roast lamb) to tough then it becomes tender. Keep the meat submerged as best you can but even if not submerged, it will becomes pull-apart tender with time. Do you know if your oven runs a little cool?? N x
Hello, I have a 10.69lb leg of lamb. How long to cook? Thanks!
Hi Brenda, sorry for the delayed response – for every added lb, I would add half an hour – so the main cook you’ll probably need about 8 hours cooking. If you take it out and it’s not quite tender, just cook a little longer. N x
The table for cooking times helps with bigger pieces but not smaller…I have two tiny legs – 650g and 725g. Not sure how long to leave them in the oven, afraid of overcooking them!!
HI Jennee, sorry for the delayed response – I would cook for about 2.5 hours upside-down, covered and then proceed to cook as per the chart. N x
I just made this recipe tonight and it was outstanding! I followed the recipe to a T. I have never made lamb before and was so impressed and my company raved about it as well. The meat was so tender and the gravy had such a lovely flavour. I am adding this to the list. Another 5 star recipe from this site. Love it! Thanks so much for sharing your delicious recipes.
Hi Nagi,
Wondering why you did not post or reply to my comment – 25 December? Wld love to hear yr thoughts on why my slow roast shoulder always works so well and yet my leg version did not.
Thanks
Elwood
Hi Elwood? Sorry for the delay – I have to manually approve most messages to avoid spammers getting through, I am very behind because lots of people left messages around Christmas but I haven’t been working! I will try to find it – N x
Hi Nagi,
Wondering why you did not post or reply to my comment – 25 December? Wld love to hear yr thoughts on why my slow roast shoulder always works so well and yet my leg version did not.
Thanks
Elwood
Hi Elwood – I searched your name but couldn’t find a comment from that date. Can you tell me what you asked? Leg and shoulder are two very different cuts of meat. Shoulder is a tough cut that can only be slow cooked – it takes hours for the meat to become meltingly tender, and it’s super fatty / juicy. Leg, on the other hand, can be cooked until blushing pink OR slow cooked until fall apart tender. With lamb leg, it goes like this – blushing pink (yum!), then you leave it in for longer and the meat gets tough (no good at this stage) but then you keep cooking and it becomes fall apart tender which is DELICIOUS and that’s what this recipe does. Not sure if that’s what you were asking about, just explaining the difference between shoulder and leg! N x