Combine steak, soy sauce, Shaoxing wine, and cornstarch in a medium-size bowl. Gently mix by hand until the beef is coated with a thin layer of the mixture. Marinate for 10 to 15 minutes.
Combine all the sauce ingredients in a small bowl. Mix well and set aside.
Cut the aromatics and vegetables. Add the ginger and garlic to a small bowl. Add the onion and all the chopped pepper to another bowl.
Heat 1 tablespoon of oil in a nonstick skillet (or a wok) over medium-high heat. When oil is hot, add the steak. Immediately spread the beef into a single layer using a pair of tongs or chopsticks. Sear for 30 seconds or so, until the bottom is lightly browned. Flip the beef with a spatula, until both sides are browned but still a bit pink inside. Turn to the lowest heat and remove the skillet from the stove. Transfer the beef to a plate and set aside.
Add the remaining tablespoon of oil into the same skillet and turn to medium heat. Add the ginger and garlic. Give it a quick stir until fragrant. Add the white onion and peppers. Stir and cook for 20 seconds.
Stir the sauce mixture until the cornstarch is dissolved completely, and pour it into the skillet. Stir with a spatula immediately and cook until the sauce thickens enough to coat the back of a spoon, a few seconds. Add back the cooked beef. Quickly stir a few times to coat everything with the sauce. Turn off heat and remove the skillet from the stove. Immediately transfer everything to a big plate so the ingredients won’t keep cooking in the hot skillet.
Serve hot with steamed rice or on top of boiled noodles.