1. Marinate the chicken: Place the sliced chicken in a bowl with the egg white, cornstarch, soy sauce, and pepper. Mix and marinate in the fridge for at least 15 minutes; this will tenderize the chicken.
2. Make the sauce: In a small bowl, mix together the oyster sauce, dark soy sauce, sugar, and fish sauce. Set aside.
3. Separate the fresh noodles by rolling the individual stacks against a cutting board with your hands and then pulling them apart with your fingers. Set aside. (If you’re using dry noodles, boil them according to package directions then drain, rinse under cool water, and toss in oil to prevent them from sticking).
4. Preheat a wok (or large pan) over medium high heat and add 1 Tbsp oil. Add the chicken and stir fry for 3-4 mins until just cooked through, then remove from the wok.
5. Add the eggs, scrambling them with your spatula until cooked through, then add 1 Tbsp more oil along with the gailan and garlic. Stir fry 1-2 mins until gailan is bright green and slightly tender then remove all ingredients from the wok.
6. Add 1 more Tbsp oil along with the noodles. Sear the noodles in one layer for 2-3 mins until they get a char, then add the sauce and stir fry for another 1-2 mins until evenly coated.
7. Add the chicken, egg, and veggies back in and stir fry 1-2 more mins until heated through. Turn off the heat, stir in the vinegar, and enjoy!
