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
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Permission to reprint your recipe & photo(s)? I am pairing roast leg of lamb with our upcoming Syrah release for our wine club members. Your recipe looks amazing. In the wine shipment we include a newsletter and in that is a recipe for pairing with the wine they are receiving. I am happy to give you a credit in print as well as link info to your website.
Thanks for considering this request,
Lynne
Lovely tender melt in your mouth leg of lamb. The gravy is a sensation. Only changes I made were to turn the lamb over for the last 30 mins so the top browned rather than the underside and added 1/2 a cup of red wine and 1/2 a cup of water rather than just one cup water to finish off the gravy. Make sure you skim off the fat before making the gravy as lamb creates a lot of it. Would definitely make this again.
Hi Nagi,
What time should we cook a half leg of lamb(1.1 kg) for?
Absolutely LOVE this recipe. Lamb leg used to be my roast undoing – too many varying thicknesses to get that perfect pink every time. With this recipe, who cares?! I have gotten oodles of compliments from guests whenever I make it, even though we are enjoying it from Saudi Arabia in temperatures of +40 degrees!
Thanks so much for sharing this Nagi, it will be a forever fixture in my kitchen.
Thanks for posting this amazing recipe. I used it yesterday and made the most delicious fall-off-the-bone roast. It tasted so so good and the onion at the bottom thing is a winner for flavour!
I live in Melbourne & its the perfect winter recipe, thank you for taking the time to write out the whole thing, your effort is appreciated
That’s wonderful to hear Charmaine! Thank you for letting me know you enjoyed this! N x
Hi Nagi,
If I want to roast two legs of lamb of 2kg, should I double everything in the recipe? What about the time?
Thank you so much!
PD: I already made one and it was amazing! Inviting more people over next time!
Hi Carmen! Yep double the recipe and squeeze it all in a giant pan or use 2 pans. It will take about 1.5 hours longer (add it to the covered time), from memory. But check it every now and then – just pry a bit of meat off to see how tender it is 🙂
Hi Nagi, I was wondering if I could add wine instead of some of the water? If so, would you recommend red or white?
Thanks so much!
I would like to know this aswell. I have red wine to add and but don’t know quantities I should use? I am cooking this for dinner tonight 🙂
I’m so sorry for the late reply! You can sub ALL the water with white OR red wine, it will be amazing! N x
Nagi, this roast was AMAZING! I bought a leg from Woolies that was close to 3kg. Set my alarm and put this in the slow cooker at 5am. We had friends over for dinner that night. Everyone loved it! We all ate way to much lamb, than what was good for us, and the bonus was that I had left overs for truly awesome sandwiches, the next day. Thank you, thank you. Definitely making this again and again.
That’s so great to hear Leanne! Thanks for letting me know you enjoyed this! N x PS I am far to familiar with the excess lamb eating feeling…..
I cooked the roast upside down! Only just realised when flipping?! Have I ruined it?
Hi nagi how long will a 10 lb bone in leg of lamb take?
Are you sure it’s LAMB??!! 😳
Yes I’m sure it’s lamb! It’s a leg of lamb with the bone and all it weighs roughly 9 pounds I’m sure if I remove the bone it will b about 8 but I’m not planning on having the bone removed
OMG that’s giant! I am guessing 12 hours 🙂 N x
Really excellent method, roasts have changed forever. I combined this with your yummy potatoes (with polenta crust) as well. FWIW I chucked some carrots in the liquid when turning the roast with half an hour to go, then put those carrots in with some pumpkin when the potatoes went into the hot oven.
I might try roasting with the fat cap up next time but otherwise stress-free and so delicious, thank you
That’s great to hear Dav! Thanks so much for letting me know you enjoyed this! N x ❤️
Dear Nagi,
What is the recipe for the beef broth? Thank you.
I’m afraid I don’t have one on my site yet! 🙂
Best lamb roast ever
My leg is only 1.65kgs how much less shall I cook it Nagi … very excited to try tonight!
Hi Cate! Use the 2kg time less 30 minutes for the slow cook time 🙂
Hi Nagi,
I had to write to share that this is the third weekend in a row that I have put this recipe in the oven early on Sunday morning before rushing out the door to take boys to rugby. Late lunch on Sunday is a real treat and the boys lamb and gravy sandwiches for school lunch on Monday are very popular. Love your website and recipes, thank you so much for sharing.
That’s great to hear Tan! So pleased you love this as much as I do – and fits in around rugby runs!!! N xx
Hi – if you are getting a bigger leg (or using 2 legs) to 3.5kg do you need to increase the liquid? If so an equal part of water and broth? How much extra would you need? Thanks
Hi Sally! Use the recipe scaler by clicking on servings and sliding it up until the lamb weight changes to what you are using 🙂 That will change all the ingredients for you!
Nagi, just wondering!! Is it possible to do a roast in a ceramic baking dish as I don’t hav a metal one. Thanks!!
That’s fine Man! Just as long as it fits 🙂 N x
Can I put the oven on a higher temp to cook faster, what temp would you recommend ?
Hi Abby! Unfortunately I don’t recommend that because if the temperature is too high, the meat will cook too fast on the outside and dry it out before the inside is lovely and tender. Sorry to disappoint! 🙂 N x
Thank you so much for a recipe that never fails. Its so beautiful,melt in your mouth and devoured in secs!
Love it!
I love that you love this as much as me! 🙂 N xx
Our family roast is forever changed, Thank you!
I’m glad to hear you enjoyed this Aisha!!! Thanks for taking the time to let me know 🙂 N x