2tablespoonscornstarch(mixed with 2 tablespoons water to form a cornstarch slurry)
Start by marinating your chicken. In a bowl, add the sliced chicken, 3 tablespoons water, 1 tablespoon oyster sauce, 1 teaspoon cornstarch, and 1 ½ teaspoons vegetable oil. Rub the marinade ingredients into the chicken with your hands until all the liquid has been absorbed by the chicken. Set aside for 10 minutes.
Boil water in your wok and blanch the broccoli for 1 minute (or 2 minutes if you like your broccoli softer). Drain and set aside.
Clean and dry your wok. Place it over high heat until smoking. Add 2 tablespoons vegetable oil and sear the chicken until opaque on all sides (this shoul d only take about 3 minutes). Turn off the heat, remove the chicken, and set aside. The chicken will be about 90% done, but will be cooked again at the end.
Without washing the wok, set the flame to medium heat. Add another tablespoon of oil, along with the garlic and ginger (if using). Stir the garlic and ginger for 5 seconds and add the Shaoxing wine around the perimeter of the wok. Then pour in the sauce mixture. Use your wok spatula to stir the sauce around the sides of the wok to deglaze, and let it come to a simmer.
Stir up the cornstarch and water slurry and drizzle the mixture into sauce while stirring constantly. Allow the sauce to simmer for 10 to 15 seconds until thick and gravy-like.
Toss in the chicken and its juices and the blanched broccoli. Stir-fry until the chicken and broccoli is coated in the sauce.
At this point, you can make adjustments. If you like your brown sauce darker, add a dash more of dark soy sauce. Add more cornstarch slurry if your sauce is too thin, or more chicken stock or water if the sauce is too thick. Serve with steamed rice.