Add about 1 tbsp of your choice of Chinese black sauces. Add a bit of sugar or ground black pepper at this point, if you want. If you want a thicker sauce, add about 2 tsp of flour to the marinade. It'll thicken when the beef cooks. Set aside.
Wash broccoli and cut into 2-inch florets or sections.
Peel and smash 3 cloves garlic.
In a sauce pan or wok on high heat, drizzle a bit of oil and add garlic. Quickly saute and then add beef strips, minus the marinade.
When the beef is seared, add the rest of the marinade and the broccoli florets and saute again.
The dish is done when the broccoli has softened to your liking.