Slice the beef into ⅛-inch thick slices. Recommend using beef chuck, flank steak, strip steak, and sirloin.
Marinade the beef with 1 Tbsp of soy sauce, 1 Tbsp of oyster sauce, 2 tsps of brown sugar, ½ tsp dark soy sauce, and ¼ tsp of baking soda and mix well. Set it aside for 10 minutes.
While waiting, slice ½ of a sweet onion thinly. Smack 4 green chilies to release the flavors and cut it into bite-size damon shapes (If you don’t eat spicy food, use bell pepper). Crush 5 cloves of garlic, smash and peel them. If your sesame seeds and cumin seeds are raw, toast them in a wok over medium-low heat for a minute or 2 and set them aside.
Turn the heat to high and heat the wok until smoking hot. Add oil and swirl the oil around to create a non-stick later at the bottom. Add the marinaded beef and let it stir for 2 minutes or until nicely charred.
Drizzle 2 Tbsps Chinese cooking wine from the side of the wok to help to deglaze the bottom.
Add the onion, chili pepper, and garlic. Stir for 1.5 minutes or until the vegetables are slightly soft.
Add the ground black pepper, red chili flake, roasted cumin seeds, sesame seeds, and ¼ tsp of salt. Continue to fry for 30 seconds or until everything is well mingled.
Serve with white rice.
