First prepare the beef. Cut the beef fillet into 30g pieces. Place the pieces end-grain face down on a chopping board, cover with cling film and use a steak mallet to beat them flat to the thickness of a beer mat.
Generously coat each piece in black pepper. Stack up the pieces and wrap in cling film until ready to cook, but don’t refrigerate.
Heat a large frying pan until hot. When hot, season the beef pieces with salt and add 25ml olive oil to the pan. Immediately place the beef pieces in the pan, keeping them separated. Scatter over the quartered mushrooms and cook hot until the meat is browned (3-4 minutes). Keep moving the mushrooms around the pan. Add the butter.
Turn the meat, and continue cooking for another 3 minutes, while still moving the mushrooms around until caramelised and dark.
Now work fast. Add the whisky (this may cause flames!), and then the stock and reduce until nearly all the liquid is gone, now add the cream and reduce until thickened, but not too thick.
To serve, tip out the beef, making sure you scrape out all the sauce and mushrooms from the pan – the sauce is the key part of this dish. If the sauce is too thick, add a splash of water in the pan and stir over the heat to loosen the sauce. Serve with the chips and salad on the side.
For the chips, carefully heat the beef dripping in a wok to 120C (we use deodorised beef dripping sold in blocks, which makes the chips taste amazing! But use veg or sunflower oil if you prefer). Place the cut potato chips in for 8 mins. Remove with a slotted spoon and pat dry with a tea towel.
When almost ready to eat, reheat the dripping or oil to 190C. Place the blanched chips back in for 2 mins, until golden. Remove, drain on absorbent cloth, season immediately with salt and pepper and serve.
Serve with a green salad. I like it with lightly dressed rocket and Parmesan salad.