For the beef with rice noodles, pak choi and mushrooms, soak the rice noodles in boiling water according to package instructions.
Meanwhile, rub the beef with olive oil, cumin and a pinch of salt. In a very hot frying pan, sear on both sides.
Fry the onion, ginger and chili for a few minutes, then add the mushrooms, clear soup and pak choi. Drain the noodles and add to the frying pan. Mix and season.
Arrange the noodles and pak choi in a deep plate, slice the meat, place it on top, pour the clear soup over it and serve the beef with rice noodles, pak choi and mushrooms.