Make the sauce by combining soy sauce, Shaoxing wine, oyster sauce, sugar, cornstarch, sesame oil, and ½ cup of water in a bowl. Set aside.
Slice the meat thinly (about ¼ inch) against the grain or across the muscle fibers.
Add 2 tablespoons of stir-fry sauce to the meat and mix them together.
Add baking soda and cornstarch. Mix them well, so they are evenly distributed. Velvet the meat for about 15 minutes while you prepare the rest of the ingredients.
Set your wok or skillet over high heat. Add a bit of oil to coat the bottom when the pan is almost smoking. Spread the meat in a single layer.
Sear for about 2 minutes without touching them. Let the other side brown for another minute. Transfer to a plate.
Cook onions and red bell peppers for a minute until slightly blistered. Add scallions and push them to one side. Slightly lower to medium-high heat at this point.
Add a bit of oil and sauté ginger and garlic for about 30 seconds. Toss them all together.
Add meat and sauce to the pan. Let the sauce slightly thicken for about 30 seconds.
Add some ground pepper and mix them together. Turn off the heat.
Notes
Beef: My favorite cuts for stir-frying are flank steak and flat iron steak. Chuck steak is an economical choice. Boneless short ribs with their deep marbling are excellent if you don't mind spending more. Other good options are beef sirloin, skirt steak, and flap meat.
Baking soda: It breaks down the tough fibers of an inexpensive cut of beef, making it tender and velvety. Also known as sodium bicarbonate, it is the same ingredient used in baking, cleaning, and neutralizing odors.
Shaoxing wine: It is an amber-colored Chinese rice wine that enhances the flavors of the dish. Substitute with another Chinese cooking wine, dry sherry, or Japanese rice wine (sake).
Oyster sauce: It is thick and umami-rich with a mild briny flavor like that of oysters.
Sesame oil: Use the dark-colored variety made from toasted sesame seeds. It has a strong nutty flavor and aroma used for seasoning. Add it at the end of cooking, but use it sparingly as it can be overpowering in excess.
Options for veggies: Broccoli, carrots, mushrooms, snow peas, baby corn, snap peas, cabbage, or bok choy