Soak the noodles in warm water for 20 minutes.
Drain the noodles. Add a teaspoon of cooking oil or olive oil over the noodles and coat them with your fingers. This is to loosen them up so they do not stick together and become clumpy. Use this with fresh ho fun or noodles as well.
Thinly slice your flank steak against the grain.
Marinate the beef with the prepared sauce above. Let it sit for 15 to 20 minutes in room temperature.
Strain the beef of any residual liquid before cooking.
Heat up cooking oil over medium-high heat in a clean wok.
When the oil heats up, add the beef strips to the wok. Let the strips sear for about 30 seconds.
Proceed to stir fry the beef for a few seconds more until it is halfway or slightly more than halfway cooked. Remove the beef strips from the wok and put on a clean plate. Do not cook the beef fully because you’ll be adding them to the noodles later. Cooking them fully now may result in overcooked and tough beef.
In another clean wok, add a tablespoon of cooking oil. When it heats up, add your white onions. If you have sliced bok choy (or any other vegetables of choice), stir fry them here together with the white onions.
When the white onions show a tinge of brown, use your spatula to push both onions and vegetables to the side of the wok. Turn up the heat to make your wok is as hot as possible.
Add the rice noodles. Give them a quick stir, then pour the noodle sauce over it.
Stir for even mixing.
Add the cooked beef and bean sprouts. Mix everything together.
Break an egg over it and mix. Optional, but my favorite.
Add the green onions. Stir fry and mix for a bit more.
Remove from heat quickly and transfer to plate. Serve and enjoy!