Start by making the marinade. In a bowl, combine one tablespoon of light soy sauce, one tablespoon of dark soy sauce, half a tablespoon of corn flour and half a tablespoon of sesame oil and stir.
Use a meat tenderizer to bash the beef strips really well, until almost flat.
Add them to the marinade, cover the bowl with kitcken foil and leave to rest for at least an hour.
Boil the noodles according to the package instructions. Drain the water, add a splash of sesame oil and toss well. Set aside.
Add half of the vegetable oil to the wok and fry the beef strips in batches, about 2 minutes on each side, until cooked through.
Remove from the wok and set aside.
Add the remaining vegetable oil to the wok, chop the onion, garlic and ginger and fry for about 30 seconds.
Break the broccoli into small florets, add to the wok and stir fry for 2 minutes.
Combine all the ingredients for the sauce: soy sauces, sesame oil, rice vinegar and sugar, and pour it over the broccoli.
In go the beef and noodles, stir well to combine, add the chopped parsley and remove from the heat.
Serve immediately.