Heat the oil and butter in a large frying pan, fry the sliced onion over a medium heat for about five minutes until it's soft.

Add the chestnut mushrooms and fry for a couple of minutes until they soften.

Add the chopped garlic and cook for 1 minute. Then transfer the mushrooms and onions to a plate and place the pan back on the heat.

Once the pan is hot, fry the beef until you get a nice brown colour all over.

Pour in the brandy, then cook for 2 minutes. This is optional, skip this step if you'd prefer.

Add the onion, garlic and mushrooms back into the pan with the beef. Stir well.

Pour in the beef stock, then add the creme fraiche and the dijon mustard. Stir well and cook for 2-3 minutes. Taste for seasoning.

Sprinkle over the chopped parsley and serve immediately with pasta.