Place the Dried glass noodles (mung bean vermicelli) in a large bowl and cover with warm Water; soak until pliable (about 8–10 minutes), then drain and set aside.
Trim and thinly slice the Boneless chicken thigh; toss briefly with a splash of Fish sauce and a pinch of sugar to season and set aside to marinate while you prep the vegetables.
Crack and beat the Eggs lightly in a bowl.
Peel and finely chop the Garlic. Slice the Yellow onion into thin wedges, julienne the Carrot, shred the Cabbage, cut the Tomato into wedges, and chop the Chinese celery and Spring onions (scallions) on the diagonal.
Heat a wok or large skillet over high heat and add a couple tablespoons of Neutral cooking oil. When hot, pour in the beaten eggs and quickly scramble until just set; transfer the eggs to a plate.
Return the wok to high heat with a little more oil if needed. Fry the chopped Garlic briefly until fragrant, add the marinated Boneless chicken thigh and stir-fry until cooked through and lightly browned.
Add the Yellow onion, Carrot and Cabbage to the wok and toss for a minute or two until they begin to soften. Stir in the Tomato, Chinese celery and most of the Spring onions (scallions), reserving a little scallion for garnish.
Push the vegetables and chicken to the sides of the wok, add the drained Dried glass noodles (mung bean vermicelli) and a splash of water if the noodles are sticking. Season with Oyster sauce, Light soy sauce, a dash of Dark soy sauce for color, and a teaspoon of Sugar. Toss everything together gently so the sauce coats the noodles evenly.
Return the scrambled Eggs to the wok, fold them through the noodles and vegetables, and stir-fry briefly until everything is heated through and well combined.
Taste and finish with a grind of Ground white pepper and additional Fish sauce or Light soy sauce if it needs more saltiness. Serve hot, garnished with the reserved Spring onions (scallions).
