Sort, clean, wash and drain the spinach. Peel and finely chop the onion. Peel, quarter, core and slice the apple. Melt the herb butter. Fry the onion and apple in it.
Sprinkle with 2 pinches of sugar and steam for 3-4 minutes. Fold in the spinach and let it collapse. Season with salt and pepper. Keep warm.
Pat the fillet dry and cut into 4 steaks of approx. 5 cm thickness. Heat the oil in a frying pan. Fry the steaks for 1-2 minutes on each side. Switch down to medium heat. Then continue frying for 3-4 minutes on each side for one pink steak (medium).
Season with sea salt and coarse pepper. Wrap in aluminium foil and let it rest for 3-4 minutes.
Arrange the steaks with the apple spinach. Garnish with long pepper if desired. Roast potatoes taste good with it.