To a bowl, add the sliced beef along with the baking soda and water. Massage the beef with your hands until all the liquid is absorbed. Pour in marinade ingredients: cornstarch, oil, and oyster sauce, and salt.
Set aside to marinate for at least 30 minutes.
Make sauce mixture by mixing together the stock, sugar, soy sauce, dark soy sauce, oyster sauce, sesame oil, and white pepper. Set aside.
Bring a pot of water to a boil and blanch broccoli for 30 to 60 seconds. Drain, and set in a bowl of ice water for 60 seconds, drain again, set aside.
Heat pan, or wok over high-heat. Add 2 tablespoons oil and sear the beef on both sides until browned for 2-3 minutes. Turn off the heat, remove the beef from the wok, and set aside.
Set the pan over medium heat and add another tablespoon of oil along with the garlic and ginger.
Next, add in the sauce mixture you made earlier. Stir the sauce around the sides of the pan to deglaze it. Bring the sauce to a simmer. Stir cornstarch and water into a slurry to ensure it’s well combined, and drizzle the mixture into sauce slowly little by little while stirring constantly. Allow it to simmer and thicken for 20 seconds.
Toss in the blanched broccoli and seared beef (along with any juices). Mix everything together over medium heat until the sauce coats the beef and broccoli. If the sauce seems thin, turn up the heat and reduce it further, or add a bit more cornstarch slurry. If the sauce is too thick, add a splash of chicken stock or water. Serve with of steamed rice!
