Dice the bacon and leave it in a pan. Finely chop the onion, sweat. Add the mushrooms and simmer over medium heat. A minute or two doesn`t matter here.
Sear the steaks in a pan for about 2 minutes on each side, then wrap them in aluminum foil and place in the oven at 150 ° C for 20 minutes.
Finely chop the parsley.
10 minutes before the steaks are ready, add the crème fraîche to the mushrooms, add the parsley and simmer briefly. Serve immediately.