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…
I made basically this recipe this past weekend, but also added smoked paprika and dried thyme and used an oven bag just to ensure it was extra succulent! It got rave reviews!! I did two big legs for a crowd of 20 and now i have quite a bit leftover plus I saved the bones. Do u have a nice recipe for scotch broth to use it all up?
I don’t sorry Anna!! Feelfree to pop it on my recipe request page though 🙂
Cooked this for the first time today. The recipe worked exactly as described (I was sceptical about the gravy method but needn’t have worried!) We are not keen on pink/rare lamb, so this is the perfect dish for us, lusciously tender & falling off bone. Thank you Nagi, I’ll be trying more of your recipes
I’m so glad you gave it a shot Kate!!
Hi
I cooked this for the fam last night and it was delicious!
I have a question though re the liquid remaining following cooking – There was far too much remaining for the gravy so had to pour cups of it out to make gravy. I thought the liquid would had absorbed and steamed off more?
Please advise thank you.
Hi Louise, that depends on how much liquid comes out of the lamb – it’s different ever time 🙂
Wonderful recipe! Fool proof! Always requested at gatherings.. firm favourite with my 2 rescue dogs as bones fall out and cool quickly for them.
what a lovely recipe. thank you for sharing it nagi. I have made this several times already and everyone in my circle just loved it.
That’s lovely to hear Paul, thanks so much for letting me know!
The best roast lamb ever. Made it for Christmas Day it was magnificent. Slow roasted it the day before and reheated on the day, hubby is a beef man, I served both, he said the lamb was better than the beef, and the gravy this makes is amazing, every one kept adding more, this is my new hostess meal so easy on the day if you do it the day or night before
I used all Nagi’s wonderful tips to cook a 3.5 kg leg of Dartmoor lamb for Xmas day. I replaced the stock and water with a bottle of red wine and it was the best thing I’ve ever put on the table. The larger leg was in the oven for 6 and a half hours and it was perfect. All my guests say thank you!
Amazing. Made this in the bbq with the lid down.
:2. The upper side of the lamb leg has more meat so we want to roast that partially submerged in the liquid for most of the cooking time. The upper side of the lamb is rounder and usually has more fat. The underside has less fat and is more flat.:
I don’t want to be pedantic, but this bit really confused me. I boggled my own head trying to decide ‘which way is up’. 🙂
Love this recipe! Along with a lot of your other recipes.
Just a question though with this one, can this be done with a boneless leg of lamb?
Nagi Just wondering about this lamb roast looks well done. I do not see any pink in the lamb. Is that correct? or am I missing something. we like it medium and pink….Thank you
How many hours for a 7 lb leg of lamb and what temperature?
I made this recipe last year for Christmas and it was amazing! This year I’ll be making it in the electric roaster. Are there any special considerations I should have regarding using the roaster instead of the oven?
Thank you for this lovely recipe! I’m going to be attempting it on Christmas. eve. Your recipe calls for 750ml beef broth? Is this fresh broth or powder that has been mixed with water? Also, can I substitute with beef stock?
Hi Melissa, stock and broth are the same thing – you could use either. If you don’t have them you can make it up using a concentrate or powder – N x
I’ve never ever commented on a recipe, but this time I just HAVE to say THANK YOU!!!!!! This works on South African lamb as well! 😉 This was my first leg of lamb ever and with both my mother and mother in law visiting (feel the pressure…), I could hardly stand all the unasked for advice and skeptic remarks throughout the whole cooking process, especially after telling them I found a recipe on the internet, and especially when my leg of lamb took 45 minutes longer than your recipe specified (I guess mine was a bit bigger than 2.25kg)…….BUT…….!!!!!! Once dinner was on the table and the first bites were taken, I could just sense their total unbelief that an internet recipe could produce such a masterpiece. Your recipe silenced their skepticism and “I always do it THIS way” remarks. They sheepishly (pardon the pun) expressed their awe! Many, many thanks!!!
I have had lambe a hundred different ways. Had my first taste of lambe when I was 40. Since then cant get enough. The recipe was simple, easy and very tasty. Really loved it.
That’s great to hear Douglas!
Hi again, sorry, I should have included the video I was referring to regarding the salad – it was the Sunday Dinner video with the classic leg of lamb recipe.
Nagi, the lamb looks absolutely delicious and I can’t wait to make it! By the way, the salad you are tossing in your video looks amazing too! Do you have a recipe for that you can share? Love everything you make!
More mouth watering recipes from your bottomless collection !
I’m in outback qld and do a monthly shop in nearest town 112km away.
Forgot the leg of lamb yesterday but have a fresh whole chook.
I’m going to do the long and slow leg lamb recipe with it and use chicken stock of course.
I go through your recipes at 5-6am most mornings before getting out of bed.
Makes me want to eat a whole beast for brekky.
Haha I love this!
Hello, can this recipe be adapted to use BONELESS LEG OF LAMB?
Hi Dee – yes you can use a boneless leg if you prefer – N x
Would the cooking time change for boneless? That seems to be all I can find around my area. I can only fins shoulder chops, not a roast, either. :/
The best lamb roast ever !
The family loved it .
Moist delicious lamb and the gravy is superb .
Thanks so much for letting me know!