1. Wash and cut broccoli into pieces.
2. Slice beef steak into small strips.
3. Put the sliced beef into a bowl. Then, add oyster sauce, soy sauce, salt, brown sugar and sesame oil.
4. Mix it well. Let it marinate for at least 15 minutes before cooking.
5. Meanwhile, pour water into a pot. Then, add salt and vegetable oil.
6. When the water is boiling, put the broccoli into the pot and cook for 2-3 minutes or until the broccoli is soft. However, do not overcook them.
7. After that, drain the water and rinse the cooked broccoli with cold water, so the broccoli will retain its bright green color.
8. Lay the cooked broccoli on a plate. After that, set them aside.
9. Pour vegetable oil into a non-stick pan, turn on fire medium high. Add garlic, ginger and stir fry them a little bit.
10. Next, put the marinated beef into the pan and stir fry them a little bit.
11. After, pour water into the beef.
12. In a small container, add cornstarch and 2 water. Mix it well.
13. Lastly, pour the cornstarch mixture into the beef and keep stirring until it's thickened. Then, pour the beef and sauce over the plate with cooked broccoli.