Marinate Beef: In a mixing bowl, combine sliced flank steak, cornstarch, baking soda, a drizzle of neutral oil, and a splash of water. Mix thoroughly and let it marinate for at least 30 minutes.

Prep Vegetables: While the beef marinates, wash and chop the bok choy into bite-sized pieces, slice the bunashimeji mushrooms, and trim the snap peas.

Make Sauce: In a small bowl, whisk together warm water, light soy sauce, dark soy sauce, oyster sauce, sesame oil, and sugar until well combined.

Heat Wok: Preheat your wok over high heat until lightly smoking, about 3–5 minutes.

Sear Beef: Add neutral oil to the hot wok, swirl it, and add the marinated beef in an even layer. Sear for about 30 seconds on each side.

Remove Beef: Carefully remove the seared beef from the wok and set aside to rest.

Cook Vegetables: In the same hot wok, add more oil if necessary, then stir-fry minced garlic and ginger for about 15 seconds.

Add Vegetables: Quickly toss in snap peas and bok choy, stir-fry for about 20 seconds until bok choy wilts slightly.

Combine: Pour prepared sauce into the wok, add back the beef, and mix until well coated. Cook together for a minute.

Thicken Sauce: Prepare a cornstarch slurry, drizzle it into the wok while stirring and cook for about 20 seconds until sauce thickens.