Peel the potatoes, wash and cook them covered with salt water for about 20 minutes. In the meantime cut the Chinese cabbage into fine strips and wash them. Scald tomatoes with boiling water, quench, skin, seed and cut into cubes.
Peel and chop 1 onion. Heat 1 tablespoon of oil, fry onion and Chinese cabbage for about 5 minutes, season with salt and pepper and set aside. Wash the beef fillet, dab dry and cut into strips.
Peel the remaining onions and cut into rings. Heat the remaining oil in a coated pan and fry the fillet strips with the onion rings for about 5 minutes and season with salt and pepper. Heat the Chinese cabbage, season with soy sauce and add the diced tomatoes.
Arrange fillet strips and Chinese cabbage on plates. Drain the potatoes and add them. Garnish with a bunch of parsley.