In a bowl, add the beef along with oyster sauce, brown sugar, soy sauce, fish sauce, grated garlic, baking soda, ground black pepper, and sesame oil. Marinate for 30 minutes or overnight for best results.
Heat a wok over high heat with 2 tablespoons of neutral oil and add the marinated beef. Sear for 30 seconds until the beef is seared, then toss for 2 minutes until the marinade is caramelized and the beef is done to your liking.
Add onion in another tablespoon of oil and stir fry until softened. Add back the beef, toss with the onions and enjoy.
Serve with sliced cucumbers, tomatoes and freshly steamed white rice if desired.
Notes
What to Cook Shaking Beef in: Due to the "shaking" motion, I recommend using a wok or large pan that you can handle comfortably. Traditionally this dish is made in a wok and that is my preference; however, I know not everyone is comfortable handling a wok. Avoid using a nonstick pan when cooking initially, as it will not give the Shaking Beef its signature sear.Avoid Overcrowding the Pan: A signature of Shaking Beef is the sear on the steak cubes from cooking in a hot wok or pan. If your wok or pan is too small, or if you are cooking too much steak at once, your Shaking Beef will not get a chance to sear. Instead, it will steam from its own juices. Make sure to use a large enough wok or pan and if needed, cook in batches.Avoid Overcooking the Beef: Once the beef has been cooked, remove it promptly to avoid overcooking. When adding the beef back into the wok or pan to incorporate with the onions, toss quickly and then remove immediately. We do not want the beef to continue cooking in the wok or pan!
Making Ahead and Reheating
Shaking Beef tastes best when served immediately.If you have any leftover Shaking Beef, you can store it in an airtight container in the refrigerator for up to 3 days. I like to reheat leftover Shaking Beef by reheating it in a nonstick pan for 3-4 minutes until just warmed through. You don't want to overcook the steak!If you want to make Shaking Beef ahead of time, I recommend marinating it only a day in advance and leaving it in the refrigerator. Before cooking, bring the marinated beef back to room temperature before cooking. (Otherwise you may not get a good sear without overcooking the beef.)