The Marinade: Put the beef in a bowl, add 2 teaspo0ns Premium soy sauce and baking soda. Mix to combine well. Let marinate at room temperature for 15 minutes.

The Sauce: Whisk together the sweet dark soy sauce, oyster sauce, remaining 2 teaspoons Premium soy sauce, and sugar in a small bowl.

Bring a medium pot of water to a boil. Add the beef and cook for 20 seconds, stirring once. Drain the beef, transfer to a large plate in a single layer, and leave in the refrigerator until cooled, about 10 minutes (this will stop the beef from overcooking). This step can be done several hours in advance.

Cook the dish in two batches: Heat half of the oil in a large non-stick pan, cast-iron pan, or flat wok over high heat until the oil begins to shimmer. Add half of the eggs (being careful because it will splatter). Let the eggs sit until they just begins to set, about 30 seconds, then, using a spatula, scramble them. Add half of the garlic and cook for 20 seconds longer. Stir in half of the noodles, beef, and sauce and cook, stirring constantly, for 2 minutes. Add half of the choy sum and cook until it just begins to wilt. Remove from the heat and stir in half of the bean sprouts, chilies, pickling juice, and white pepper and transfer to a shallow bowl or platter. Repeat the process with the remaining ingredients. Garnish with cilantro and chili flakes.