Peel and wash the potatoes and cut them into thin slices. Heat 1 tablespoon of oil and fry the potatoes for 15-20 minutes, turning frequently. Wash the meat, dab dry. Cut the fat edge 2-3 times.
Peel onion and cut into thin rings. Heat 1 tablespoon of oil in a second pan. Fry the onion in it for about 5 minutes, take it out. Fry steak in hot onion fat for 2-3 minutes on each side (pink/medium).
Season the steak with salt and pepper and remove from the pan. Wrap in aluminium foil and let it rest for about 2 minutes. Warm the onion once more in the hot frying fat. Wash parsley, dab dry and cut into fine strips.
Season the fried potatoes with salt and pepper. Arrange steak with onions and fried potatoes. Add remoulade and sprinkle with parsley. Serve with salad.