Slice the pork tenderloin thinly with a sharp knife, taking off the white sinew if you have any

Place the pork slices between two sheets of cling film and bash them with a rolling pin until they're very thin

Place the thin pork slices in a bowl or container and add 2 tsp olive oil, 1 tsp lemon juice, 1 garlic clove, (peeled and crushed) and black pepper. Leave for 30 minutes. If you can't wait that long it doesn't matter, you just want to infuse the pork with the garlic and lemon juice

Trim and thinly slice the mushrooms (I don't wash mushrooms normally unless they're wild ones which are likely to have grit in)

Peel and thinly slice the onion

Melt some butter and a drop of olive oil in a frying pan and fry the onion gently for about 5 minutes until they're soft but not browning

Add the pork, draining off as much as the marinade as possible and fry for around another 5 minutes making sure that the pork is browned on both sides

Add the mushrooms and fry until they'e soft

Add the sherry and boil until it is reduced to about 1 tablespoon, season with salt and pepper and then add the creme fraîche and heat gently until the sauce is almost boiling,

Serve and enjoy!