HOW TO COOK ROAST LAMB

how to cook roast lamb

Discover how to cook roast lamb with our expert guide to a truly memorable roast. Whether you’re aiming for ‘ooos’ and ‘aaas’ around the table with a traditional roast leg of lamb or taking things slow with a meltingly tender lamb shoulder, we’ll show you how. Learn which is the right cut of lamb for your roast and nail the cooking times (plus that all-important rest).

See & shop British lamb

Essential roast lamb cooking tips

You should typically allow 225g of meat per person.
Take the lamb out of the fridge 30 minutes to 1 hour before cooking.
Sit your joint on top of roughly chopped vegetables; they’ll soak up the delicious juices.
Baste 2-3 times during cooking with all the juices.
Rest the lamb after cooking. This makes for a more tender serving.

Ready to put these tips into practice?

Our one-tin roast leg of lamb with herbs & potatoes or slow-cooked leg of lamb with sherry are brilliant examples of how cooking everything in the same tin lets the potatoes soak up all those lovely lamb juices, with the added bonus of less washing up.

How to cook a leg of lamb

Waitrose chef Alex Szrok shows how to cook the perfect roast leg of lamb.

Oven 180ºC | Fan 160ºC | Gas 4

Half or whole leg cooking times:

Medium: 25 minutes per 500g, plus 25 minutes

Well done: 30 minutes per 500g, plus 30 minutes

Boneless leg cooking times:

30 minutes per 500g, plus 30 minutes

Leg of lamb recipes

How to slow cook lamb shoulder

Oven 170ºC | Fan 150ºC | Gas 3

Slash the skin and rub oil and rosemary over the meat.

Pour over stock and wine, cover tightly with foil and leave in the oven to cook slowly for 40 minutes per 500g, plus 25 minutes.

Remove the foil halfway through.

Try our slow-roast shoulder of lamb with garlic

How to cook rack of lamb

Oven 200ºC | Fan 180ºC | Gas 6

Preheat a nonstick frying pan and fry the lamb on all sides until well browned all over.

Transfer to a small roasting tin and cook to medium (14 minutes), or well-done (16 minutes).

This is based on a rack that is approximately 380g.

Try our rosemary & anchovy rack of lamb

Which cut of lamb to use?

Now for something different...

How to cook lamb skewers

Everyone loves a kebab, right? Waitrose chef Alex Szrok fires up the barbecue to grill tender lamb steaks, finished with a punchy herb and anchovy sauce.

See & shop the recipe

Which wine pairs best with roast lamb?

More delicate cuts, such as rack, pair best with elegant wines like a Bordeaux blend. If you're going for a slow-cooked shoulder, match it with bolder options like Malbec or Rioja.

Cooking for a crowd?

Remove all stress from your Sunday roast with our Food Made to Order service, which offers prepared roasting joints serving up to 20 guests, all ready to go in the oven.

Shop Waitrose Entertaining

All our LAMB is BRITISH – all year round

We like to keep our lambs happy, with room to frolic and graze, and our British farmers share our commitment to higher welfare standards. We’re proud of our animal welfare policies and work hard to maintain them while supporting our brilliant farmers and suppliers.

Find out more about how our lambs are reared

Your roast-lamb cooking questions answered

We answer all your roast-lamb need-to-know questions. Discover which sauces pair best with lamb, how to keep it juicy every time and much more...

There isn’t a single right answer here, so it really comes down to how you like your lamb (no pressure). When roasting, there’s no need to cover it. Leaving it uncovered helps the top brown nicely and brings out that rich, roasted flavour we’re all after. If you’re slow-cooking, a loose tent of foil for part of the cooking time can be a real help, keeping the lamb juicy and stopping it from drying out. If the lamb is starting to look really dark and you still have a while left on the cooking time, loosely cover it in foil to stop it burning.

Cutting corners is the one mistake that tends to lead to all the others when roasting leg of lamb. Trying to save time by cooking it straight from the fridge can leave you with uneven results – let your lamb come up to room temperature first.

This leads to the next trap: judging ‘doneness’ by eye, as lamb is a great bluffer. The most reliable way to check is with a meat thermometer. Leave it in the thickest part for about 20 seconds. For medium to medium-well done, you’re aiming for 60 to 65°C. For a low-tech option, slide a skewer into the thickest part, avoiding the bone, then pull it out and check the juices. If they run freely with a pink, rosy hue, you’re good to go.

For tender lamb every time, it’s important to choose the right cut for the way you plan to cook it. Tougher cuts such as lamb shoulder really shine when cooked low and slow, becoming beautifully soft and full of flavour. And don’t underestimate the power of a good rest. This time it really is about the lamb, though it’s not bad advice for the cook too. Resting allows the juices to settle back into the meat, keeping it succulent and preventing it from drying out. Even for a slightly leaner cut, like leg of lamb, you still need a relatively long cook time to tenderise the meat. For medium, aim for about 25 minutes + 25 minutes per 500g.

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