To cook the chicken, in a wok over high heat, add 1 tablespoon of the cooking oil, then add the ground chicken, salt, and white pepper, and stir-fry until cooked through. Remove and let cool slightly.
To prepare the egg mixture, in a bowl, whisk the eggs with the salt, then mix the cornstarch with the water to form a slurry and add it to the eggs. Add the Chinese chives, cabbage, carrot, bean sprouts, and the cooked chicken, then mix well.
To cook the egg foo young, in a wok over medium heat, add about 1 tablespoon of the cooking oil and heat until hot, then add a ladleful of the mixture and cook undisturbed for about 2 minutes until lightly golden and set.
To flip and finish, gently flip and cook for another 2 minutes until fully set and lightly golden, then remove and repeat with the remaining mixture.
To make the gravy, in a pot over medium heat, add the chicken stock, soy sauce, oyster sauce, and sesame oil and bring to a simmer, then mix the cornstarch with the water to form a slurry, stir again, and add to the pot and cook until thickened.
To serve, place the egg foo young on a plate and drizzle the gravy over the top and serve immediately.