Clean the mushrooms and cut in half. Chop the fillet, fry in the clarified butter in portions and remove, then season with pepper and salt. Put the mushrooms in the frying fat, sauté and season. Add half of the creme fraîche and heat. Put the meat back in the pan and let it steep briefly. Wash and finely chop the herbs and mix with the rest of the creme fraîche, salt and pepper, except for one tablespoon. Just before serving, add to the dish and cover with the rest of the herbs.