Steps

• In a bowl, combine the sliced flank steak with 1 tbsp of soy sauce, 1/2 tsp of sugar, and 1 tbsp of cornstarch. Stir until all pieces are well-coated. Let it marinate for about 15-20 minutes while you prepare the other ingredients.
• In another small bowl, whisk together the remaining soy sauce, oyster sauce, water, and black pepper. Adjust the seasoning to taste, adding more soy sauce or a pinch of sugar if desired.
• Heat your wok over medium-high heat and add 1 tablespoon of vegetable oil. Add the broccoli florets and stir-fry for 2-3 minutes, just until they turn bright green and tender-crisp. Remove the broccoli from the wok and set aside.
• In the same wok, add a little more oil if necessary, then sauté the garlic and ginger for 30 seconds until fragrant. Add the marinated beef, spreading it out in a single layer to promote even cooking. Stir-fry for about 3-5 minutes until the beef is browned on the outside and cooked through.
• Return the broccoli to the wok, pour in the sauce, and toss everything together. Let it simmer for another 2-3 minutes, allowing the sauce to thicken and coat the ingredients evenly. If you prefer a bit of heat, sprinkle in the optional red pepper flakes at this time.