Cut the steaks into very thin strips. Chop up your mushrooms. Finely slice your onion.

Put the beef slices into a large bowl. Flood the bowl with Worcestershire sauce, the curry powder and the mustard.

Give it a good stir-use your hands to get everything coated well. This should not be overly wet, it should coat the beef nicely. Cover with cling film and place it in the fridge. Marinate overnight if possible or for at least 2 hours.

Make sure you take the beef out of the fridge at least an hour before you use it. Then in a big deep frying pan, add a couple of tbsp of oil and half of your butter and fry the beef strips in batches.

Once the pieces are brown, put the fried steak back into the bowl and leave to one side to rest.

In a large frying pan melt a big knob of butter and add a bit of extra virgin olive oil. Let them heat up, the butter will start to foam and colour.

Add the onions and cook them until they are translucent, starting to brown.

Turn up the heat slightly and add the flour to the onions. Turn the temperature down a bit and then, bit by bit, add the tomato purée cook for a minute, then add the stock.

Scrape the bottom of the pan to get off any bits. Adjust the heat so the liquid is gently rolling.

Now, take the bowl with the beef in and tip into the oniony liquid. Give it a stir and now wait until the liquid reduces down into a rich, thick gravy. The beef should not be fall apart tender but really close.

Melt a large knob of butter in a frying pan. Add all the mushrooms. Fry until golden brown then add the garlic being careful not to burn it. Stir in the chopped parsley. You can do this at any stage of the cooking process and keep to one side.

Once the beef is tender, stir in the cooked mushrooms.

At this point stir in a tablespoon of soured cream and a grind of black pepper, check and see if it needs salt and add as required. Serve with the extra soured cream, spring onion and paprika.