In a large wok or frying pan heat the oil over high heat. Add the oil. Fry the beef in one layer, turning once, until brown on both sides, but juicy inside. Set beef aside.
Heat the wok/pan over the high heat again. Add onions and broccoli, stirring often to scrape up the bits stuck to the pan and also to cook the onions and broccoli until soft with a crunch, about 5 minutes.
Add the beef, its' accumulated juices, the sauces, sugar and white pepper. Stir well to reheat the beef and combine everything well. Taste. Add more fish sauce to taste, if necessary.