How to cook a leg of lamb

Whether it’s a Sunday roast, a midweek slow cook or a festive dinner for family and friends, a roast leg of lamb is a delicious and versatile joint of meat that can be surprisingly straightforward to prepare.

Here we cover everything from cooking times and portion sizes to getting the best from your joint. We also explain how to tell when your lamb is cooked and how long to rest it before serving.

Keep reading for our step-by-step recipe and expert advice on preparing and carving your roast. Plus, find out the herbs and spices that pair well with lamb.

How to cook a leg of lamb

1. Take the lamb out of the fridge at least an hour before cooking to bring it up to room temperature.
2. Preheat the oven to 220°C/200°C fan/gas mark 7.
3. Weigh the meat to calculate the cooking time. As a rough guide, allow around 20 minutes per 450g, plus an extra 20 minutes if you want your lamb medium cooked.
4. Drizzle with olive oil and rub it all over the meat before seasoning generously with salt and pepper.
5. Place the lamb in a roasting tin and transfer it to the preheated oven.
6. Cook for 20 minutes before turning the oven down to 190°C/170°C fan/gas mark 5 and continuing to cook until the lamb is done to your liking.
7. Take the lamb out of the oven, loosely cover it with foil and leave it to rest for 15-20 minutes before carving and serving.

What is the cooking time for a leg of lamb?

Once you know the weight of the meat, you can work out roughly how long it will take to cook. As a guide, the approximate cooking times for a medium leg of lamb are:

• 750g: 1 hour 5 minutes
• 1kg: 1 hour 15 minutes
• 1.5kg: 1 hour 40 minutes
• 2kg: 2 hours 5 minutes
• 2.25kg: 2 hours 30 minutes
• 2.5kg: 2 hours 50 minutes
• 2.75kg: 3 hours

If you prefer your meat well done, allow around 30 minutes per 450g, plus an extra 30 minutes. Check the cooking instructions on the packaging or ask your butcher for advice when you're buying the meat.

The easiest way to check if your lamb is cooked to your liking is with a meat thermometer. Insert the probe into the thickest part of the joint, avoiding the bone. As a guide, aim for an internal temperature of around 60°C for medium (pink) lamb or 72°C for well done.

Cooking times can also vary depending on how accurately your oven maintains its temperature. In our tests, we've found some ovens that run 30°C hotter than the temperature you've set, which could leave your lamb overcooked.

If you're looking to replace your oven, take a look at our built-in oven reviews, freestanding cooker reviews and range cooker reviews.

Does lamb leg become more tender the longer you cook it?

Lamb leg can become tender when cooked slowly, but cooking it for longer doesn't always mean better results. As the meat is relatively lean, it can dry out if overcooked. If you opt for a shorter, high-heat approach, keep a close eye on the cooking time to help the meat stay succulent.

Cuts with more fat and connective tissue, such as shoulder and shank, are particularly well suited to slow cooking, although leg can also be cooked this way. Cooking these tougher cuts slowly gives the connective tissue time to break down, helping the meat become tender.

What size leg of lamb do I need?

Not sure how much lamb you need for your guests? As a rough guide, allow around 300g-400g per person (raw weight, including the bone).

• 750g-1kg: Serves two
• 1kg-1.5kg: Serves four
• 1.5kg-2kg: Serves six
• 2.25kg-2.75kg: Serves eight

Where to buy a leg of lamb

Lamb is widely available from nearly every supermarket or butcher in the UK and Ireland. If you're not sure where to go, see our round-up of the best and worst supermarkets.

• Aldi sells British half legs of lamb as part of its Ashfields range. At the time of writing, expect to pay around £14/kg.
• Asda sells whole and half legs of lamb, with prices starting at around £13/kg at the time of writing.
• Morrisons offers a selection of lamb legs and smaller joints, with prices starting at around £14/kg.
• Sainsbury's sells British or New Zealand whole and half legs of lamb, with prices starting at around £17/kg.
• Tesco sells whole and half legs of lamb, with prices starting at around £17/kg.

A whole bone-in leg of lamb often weighs around 2kg or more, although sizes vary between supermarkets and butchers.

Crown your roast by reading our advice on how to make Yorkshire puddings

What to add to a leg of lamb

While a well-cooked leg of lamb has plenty of flavour on its own, herbs, spices and accompaniments can complement the meat and give you plenty of ways to vary the dish.

Here are some herbs, spices, sauces and condiments that pair well with lamb:

• Aioli: This creamy garlic sauce works well with lamb and roast potatoes.
• Baharat seasoning or curry powder: Use as a dry rub or mix into stews and other dishes.
• Black pepper: Create a mustard and black pepper crust, pair the lamb with a black pepper sauce or simply season the meat before roasting.
• Chimichurri: Made with finely chopped parsley, garlic, olive oil, oregano and red wine vinegar, chimichurri can be served alongside lamb or used as a marinade before cooking.
• Cumin: Rub ground cumin or cumin seeds over your lamb before cooking to create a crust.
• Garlic: Rub the meat with garlic butter or make small cuts and insert garlic cloves before cooking.
• Gravy: Use the juices from the cooked lamb to make homemade gravy.
• Gremolata: Serve with this tangy green mixture made with chopped parsley, lemon zest and garlic.
• Mint: Pair roast lamb with mint sauce or jelly, sprinkle fresh mint leaves into a side salad or make a mint marinade.
• Mustard: Rub English or wholegrain mustard over the lamb before roasting to create a punchy crust.
• Oregano: Mix with olive oil, garlic, salt and pepper and rub over the meat before roasting.
• Rosemary: A classic pairing with lamb. Tuck sprigs around or into the meat before cooking, or add rosemary to a marinade or flavoured butter.
• Tomato relish: Serve as a condiment alongside lamb.
• Thyme: Add whole sprigs to the roasting tin while the lamb cooks.
• Yoghurt or tzatziki: Serve on the side, add to a gyro or drizzle over sliced lamb.

Best red wines: find our top-rated bottles to serve with your lamb.

How to slow-roast a leg of lamb

To slow-roast a leg of lamb, cook it at a lower temperature for longer. Covering the lamb with foil for most of the cooking time can also help prevent it from drying out.

1. Take the lamb out of the fridge at least an hour before cooking so it can come up to room temperature.
2. Set the oven to 160°C/140°C fan/gas mark 3.
3. Allow around five to six hours for a 2kg leg of lamb. Bear in mind that cooking times will vary depending on the size of the joint and your oven.
4. Drizzle with olive oil and rub all over the lamb, then season generously with salt and pepper.
5. Place the lamb in a roasting tin, cover loosely with foil and put it in the preheated oven.
6. Remove the foil around 45 minutes before it’s done so the meat can brown.
7. When the meat is cooked to your liking, take it out of the oven, loosely cover it with foil and let it rest for 15-20 minutes before carving and serving.

Alternatively, you can cook lamb slowly using one of our best slow cookers.

Can you air fry a leg of lamb?

Yes, you can air fry a half or mini leg of lamb if it fits comfortably in your air fryer. A smaller joint usually works best.

A recipe from BBC Good Food suggests cooking a 1-1.2kg leg of lamb in an air fryer with garlic and oregano, and serving it with crispy new potatoes. To try it for yourself, follow these steps:

1. Take the lamb out of the fridge around 30 minutes before cooking. Make small incisions in the meat and slide in slivers of garlic, then rub the lamb with olive oil, chopped oregano, salt and pepper.
2. Heat your air fryer to 200°C, then place the lamb in the basket. Pour over half the lemon juice and arrange the seasoned baby new potatoes around it.
3. Air fry for 15 minutes, then lower the temperature to 180°C and cook for a further 45 minutes, turning the lamb halfway through.
4. Transfer the lamb to a warm plate, cover loosely with foil and leave it to rest for 10 minutes. Meanwhile, you can sprinkle the potatoes with grated cheese and lemon zest, then air fry for a further 5-8 minutes until golden and crisp.
5. Drizzle the lamb with any resting juices, garnish with oregano and serve with lemon slices.

Check in with our guide to the best air fryers to see which models we recommend.

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More roast lamb recipes

• BBC Good Food's roast leg of lamb recipe: Many of these recipes include anchovies for a salty twist, and several of them can be cooked in under two hours. You can also check out leftover lamb recipes to ensure that none of your roast goes to waste.
• Jamie Oliver's roast leg of lamb recipe: Jamie uses a marinade made up of rosemary, garlic, olive oil and lemon zest to flavour the lamb and advises cooking the joint directly on the oven bars, with a tray underneath to catch the juices.
• Nigella Lawson's roast leg of lamb recipe: Like Jamie, Nigella rubs a leg of lamb with a marinade. But she uses rosemary, oregano, lemon, orange, garlic, olive oil and salt, which, once cooked, will form a soft, fresh crust on the top of the joint. The recipe also advises cooking the meat in half an inch of water.
• Mary Berry's roast leg of lamb recipe: This crowd-pleasing recipe takes around five hours, so you’ll need to start earlier in the day. Seasoned with garlic, paprika and thyme, the lamb is then cooked with ratatouille-style vegetables and covered with foil to keep it moist.

See our round-up of all our best food and drink