Mix the sliced flank steak with the light soy sauce, oil and corn starch until combined and set aside for 30 minutes.
In a small bowl, mix the sauce ingredients together until well blended, then set aside.
Bring some water to a boil and blanche the broccoli florets for 2 minutes. Place oil into the water (optional) to give your broccoli a nice glisten. After 2 minutes, strain and set the broccoli aside.
Heat 1 tbsp oil in a wok or nonstick pan, swirling to coat evenly.
Place the ginger and minced garlic into the wok and stir fry for about 30 seconds, or until you can smell their aromas.
Place your flank steak into the same wok and sear until the the beef are 75% done. You should still see slight pink in the pieces. Transfer to a separate plate.
Give the sauce mixture a whisk to dissolve the corn starch that has settled on the bottom, then pour it into the same wok you stir-fried the beef in. Stir briefly, until the sauce thickens.
Toss the blanched broccoli florets and flank steak into the wok to combine with the sauce, for about 1 minute or until you reach the desired doneness for the beef.
Plate and sprinkle some sesame seeds (optional) over the dish. Serve over rice and enjoy!