Pic of Mustard crusted roast beef with white bean mash and walnut dressed beans

Mustard crusted roast beef with white bean mash and walnut dressed beans

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Meat mains

Mustard crusted roast beef with white bean mash and walnut dressed beans

Main Serves 2 45 min
This is a great dish using our mini roast beef joint, perfect for two. Sealed and coated with mustard and garlic, then thinly sliced and served on a creamy red onion and white bean mash. Finely chop your rosemary until it looks like breadcrumbs, this will help it cook down without leaving any sharp, hard little nuggets when you come to eat the beans.

Cook's notes

It's important to leave any cooked joint of meat out of the oven for a little while before carving. This allows the meat fibres to relax and the juices to permeate the meat, giving you a juicier joint. It really won't lose its heat too much, but if you are at all concerned about this, loosely cover it with foil.


  • 1 large or 2 small red onions
  • 10g rosemary
  • 15g fresh chervil
  • 200g green beans
  • 1 beef mini roast
  • oil for frying and roasting e.g. sunflower or light olive
  • 2 garlic cloves
  • 1 tbsp wholegrain mustard
  • 2 tins cannellini beans
  • 25g walnut pieces
  • 1 lemon
  • olive oil
  • salt and pepper
Image of Mustard crusted roast beef with white bean mash and walnut dressed beans


Prep time: 15 min
Cooking time: 30 min
  • Step 1

    Preheat oven to 220°C/Gas Mark 7. Peel and finely dice the red onion(s). Pick the leaves off the rosemary and very finely chop so they resemble breadcrumbs. Wash half the bag of chervil and leave to drain. Wash the green beans and trim off the stalk tops.
  • Step 2

    Rub the beef mini roast with a little oil and season with salt and pepper. Heat a frying pan. When hot, sear the beef on all sides to brown and seal it. Make sure it has a good dark brown colour to the outside. Transfer the beef to a baking dish.
  • Step 3

    Peel and finely chop or crush 2 garlic cloves. Mix it with the mustard and 1 tablespoon of oil. Smother it over the beef. Transfer to the oven and cook for 15 or 20 minutes for rare or medium-rare meat, or a little longer, 25 minutes or so, for well-done.
  • Step 4

    Once the beef goes in, heat 2 tablespoons of oil in a saucepan. Add the onion and rosemary. Fry for 10 minutes, stirring often. Add a splash of water if it looks like catching at any point. Next, make the cannellini mash. Drain and rinse the beans.
  • Step 5

    You just need 1 and a half tins, so keep some back in a pot in the fridge and use in lunchbox salads. Rinse out and fill 1 of the tins quarter full with cold water. Put a pan of water on to boil for the green beans.
  • Step 6

    After 10 minutes, add the cannellini beans to the onion. Add the water in the tin. Bring up to a simmer. Cook for 5 minutes, stirring often; the beans will start to break down a little and become creamy. Give them a prod here and there with your spoon to break them down further, adding a splash more water to stop them getting too dried out, if needs be.
  • Step 7

    Once cooked, remove the beef from the oven and leave it to one side to rest for 10 minutes.
  • Step 8

    Meanwhile, chop the walnuts up so the pieces are nice and small. Cook the green beans in the pan of boiling water for about 4 minutes or so, until just tender but still with a little squeak.
  • Step 9

    Drain the beans and toss with the walnuts, a little squeeze of lemon juice, a glug of olive oil and salt and pepper to taste. Season the white bean mash with salt and pepper to your taste (gently reheated if necessary). Serve with the green beans and thinly sliced beef.

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