Ultra Slow Roast Beef (and Perfect Roast Potatoes)

I am pretty sure that many A&G readers are far better cooks than me but, with Christmas looming and many of us planning to cook roast beef at some point over the holiday, I thought it might be helpful to let you in on the secret of cooking the perfect joint.

This recipe is from my friend Julia, who is renowned for her fabulously tasty Sunday lunches. We were out walking (socially distanced of course) when she mentioned that she had cooked ultra slow roast beef based on Heston Blumenthal’s recipe and how it was perfectly pink and tasted amazingly tender. Here’s how she did it…


Buy yourself one lovely piece of roast beef to suit your family’s appetite as well as for seconds!  I have to say that this way of cooking roast beef is so fantastic that people do come back for seconds and thirds, so don’t scrimp!  We weren’t left with enough to have cold roast beef sandwiches last week!

I buy either a rolled sirloin or a rolled rib.  

Firstly make sure that your beef has been sitting out at room temperature for a an hour or two before cooking.  This is important as the joint will cook more evenly if you do.

Pre-heat your oven to 120 degrees C. Season the fat with salt and pepper and then spend a few minutes searing it in a hot pan on top of your Aga or hob.  Then spread the fat with mustard.  I use Dijon, but English Mustard is just as good. 

Thermopro £15.99 MORE INFO

Lay it in a roasting dish and insert your thermometer into the middle of the beef.  Set the thermometer to 55 degrees for Rare or 57 degrees for Medium Rare.  Put it in the oven at 120 degrees for half an hour. Then turn the oven down to 80 degrees and leave it to cook for 4 – 5 hours. My Thermopro has an alarm when it reaches the correct temperature so it is very easy to use.  It is attached by a wire that you shut the door around and then a magnet on the back of the unit so that it sits on the outside of your oven door.

Once it is ready, remove it from the oven and put it on a roasting dish or plate, cover with foil and a tea towel and leave to rest for at least an hour.  This part is very important.

The beauty of this is that you can leave it to rest for as long as you like so you can be flexible with your timings.  It is still warm after an hour and a half and once you pour lashings of hot gravy over the top then it is perfect.

Now that I have been converted, I will never cook beef any other way as it always used to be a bit of a lottery for me.  Was it rare enough or wasn’t it and I didn’t like the outer edge being brownish.  With this method you achieve the most perfect pink colour the whole way through the piece of meat and it is so much more tender than the fast cooking method.  You will notice that when you get it out of the oven there really isn’t much juice in the tray as it has retained it all!

Happy Roast Beef! Julia x

Support your local butcher!


A bit more effort but I think crispy roast potatoes are such an important part of any roast. I use King Edwards which are one of the best varieties for roasties, although Maris Piper and Desirée work well too.

Place a roasting tray with vegetable oil (or, even better, goose fat) in it on the highest shelf of a 200 degree oven to get piping hot.

Thinly peel the potatoes then leave the small ones whole and cut the larger ones in half. Put them in a steamer fitted over a large pan of boiling water, put a lid on, turn the heat down to low and steam the potatoes for about 10 – 15 minutes. The tip of a small, sharp knife should go in easily without breaking the potato up.

Drain the water off (you can keep some for making the gravy later if you like) and tip the potatoes into the saucepan. Put the lid back and, holding the lid on firmly with your hand protected by a cloth or oven glove, shake it vigorously from side to side to roughen up the cooked edges of the potatoes. This is how you get those moreish crunchy edges. Carefully tip the potatoes into the hot roasting tray and turn them over so they are evenly coated with fat.

Pop back into the hot oven on the highest shelf and cook for 50 minutes or so until they are golden brown and crisp on the outside and soft and fluffy inside. I usually turn them over halfway through cooking. Sprinkle with rock salt (and a few finely chopped herbs if liked) and serve.

I love beef with an anchovy dressing – recipe here

One last tip. Julia recommends using Bisto powder not granules for a really tasty gravy. If your supermarket doesn’t stock powder, try Amazon.

Almost 800 tried & tasted recipes are at your fingertips – either type in an ingredient in the search bar (top right) or browse here

0 0 votes
Article Rating

Leave a Reply

Newest Most Voted
Inline Feedbacks
View all comments
2 years ago

How do you make your gravy if there are no meat juices please?

Annabel & Grace
2 years ago
Reply to  Polly

Hi Polly. I have just spoken with The Queen of Gravy (Julia who was the one who told us about this amazing recipe) and here is her reply:

I use Bisto Powder (not granules!) 3 heaped teaspoons, 1 heaped teaspoon flour, splash of gravy browning, glug of white wine, and the veg water. If I have any homemade chicken stock then some of that too.

Hope that helps – enjoy your delicious beef! Best wishes, Julia and Grace

2 years ago

Can I ask what is the approximate weight of the joint of beef? It sounds and looks delicious, but I am concerned about over cooking a smaller joint.

Annabel & Grace
2 years ago
Reply to  Bridgette

Hi Bridgette. I asked Julia’s advice and she said she usually buys a 4-5lb joint for 4 people with leftovers. However, whatever size your joint is, as long as you cook it to 57 degrees, you will have perfect beef. Make sure to rest it for about an hour before serving. Hope that helps. Best wishes, Grace

2 years ago

Many thanks Grace! I shall definitely try this method of cooking. It’s so important to support British farmers. Rather excited, it was my first post and I received a reply so quickly. Thank you.