Ingredients

• 675g/1½ lb beef fillet
• preferably cut from the tail end
• 65g/2½oz unsalted butter
• 1½ tbsp paprika (hot Hungarian
• if you like a little subtle heat)
• 1 large onion
• very thinly sliced
• 350g/12oz button mushrooms
• thinly sliced
• 3 tbsp sunflower oil
• 300ml/10fl oz soured cream
• 2 tsp lemon juice
• small handful of parsley leaves
• finely chopped
• salt
• freshly ground black pepper
• 450g/1lb floury potatoes
• such as Maris Piper
• peeled
• sunflower oil
• for deep-frying

Directions

• Cut the steak into slices 1cm/0.5in thick
• then cut each slice across the grain into strips 1cm/0.5in wide.
• For the matchstick potatoes
• cut the potatoes by hand into short sticks 3mm/0.2in thick or use a mandoline. Set aside in a bowl of cold water.
• Heat the sunflower oil for deep-frying
• either in a large pan or in a deep-fat fryer
• to 190C/375F.
• Meanwhile
• melt the butter in a large frying pan
• add the paprika and onion and cook slowly until the onion is soft and sweet
• but not browned.
• Add the mushrooms and fry gently for three minutes. Transfer the mixture to a plate and keep warm.
• Drain the matchstick potatoes and dry thoroughly in a clean tea towel or a salad spinner.
• Plunge the potatoes into the hot oil and fry for three minutes
• until crisp and golden. Drain briefly on kitchen paper and keep hot in a low oven.
• Using the same pan you cooked the onion mixture in
• heat one and a half tablespoons of sunflower oil until very hot.
• Add half the fillet steak and fry quickly
• seasoning and turning it as you do so
• for just over one minute. Transfer to a plate and repeat with the rest of the oil and steak.
• Return the onion mixture to the pan and pour in the soured cream. Bring to the boil and simmer for a minute or so
• until thickened.
• Return the steak to the pan and heat very gently for one minute - the beef should not be cooked any further.
• Stir in the lemon juice and parsley and serve with the matchstick potatoes.