Wash the fillet and pat dry, cut into 2 cm slices and flatten a little. Layer in a bowl and season with pepper, then soak in the 200 ml sherry.
While the meat is soaking, clean and chop the mushrooms, dice the onion and garlic.
Heat the oil in the pan. Lift the fillet out of the sherry and drain well, then fry it on both sides in a hot pan. Take the fillet out of the pan, place it on a deep plate and season with the herb salt.
Fry the bacon, onions and garlic in the pan. Then add the mushrooms and fry them. Deglaze with the sherry in which the meat was lying and bring it to the boil briefly so that the seared meat loosens and the sauce turns brown. Now stir in the sour cream and put the fillet back into the sauce with the meat juice from the plate.