Wash the fillet steaks and dab dry. Wrap the breakfast bacon around the fillet steaks and tie them tightly with kitchen twine. Heat 1 tablespoon of oil in a frying pan and fry the fillet steaks in it over medium heat for 8-10 minutes, turning several times.
In the meantime, clean the mushrooms, clean them if necessary and cut them into thick slices. Peel and finely chop the onion. Peel and wash the potatoes and grate them roughly with a kitchen grater. Season with salt and pepper.
Heat the remaining oil in a coated pan. Using a tablespoon, form approx. 4 medium-sized Rösti and fry each side for approx. 3 minutes until crisp. In the meantime remove the fillet steaks from the pan and keep them warm.
Sweat onion in the frying fat and add mushrooms. Deglaze with broth and cream. Simmer for about 3 minutes, season with salt and pepper. Drain Rösti on kitchen paper. Season fillet steaks with salt and pepper and arrange on plates with mushroom cream sauce and 2 Rösti each.
Serve garnished with chervil.