Wash the fillet of beef, dab dry and rub with pepper. Heat 15 g clarified butter in a pan and fry the fillet all around. Fry over a low heat for about 20 minutes, turning.
In the meantime, clean, wash and cut the beans into pieces and cook in boiling salted water for about 10 minutes. Clean, wash and quarter the mushrooms. Peel and finely dice onions. Heat the remaining clarified butter and fry the diced onions and mushrooms in it.
Season with salt and pepper. Drain the beans and add to the mushrooms. Remove the fillet from the pan and salt. Wrap in aluminium foil and let it rest for about 10 minutes. Melt butter. Put the egg yolk and wine in a bowl and whip it on a hot water bath until thick and frothy.
Remove from the water bath and slowly fold in the liquid butter. Season to taste with salt, pepper and Worcester sauce. Wash the tarragon, chop finely and add to the hollandaise. Cut the meat open and arrange on a plate with the mushroom vegetables.
Add tarragon-hollandaise sauce. Boiled potatoes taste good with it.