Cook the steaks to your liking in a knob of butter and then let it rest for 5 mins.
Meanwhile, cook the onions in another pan until soft.
Add the garlic and mushrooms and cook until the mushrooms have browned and are soft.
Throw the wine in and cook of the alcohol and the volume has reduced by half.
Add the crème fraîche and parsley and stir until combined and warmed through.
Serve with the steak, chips and beer.