Stir-Fry Sauce - Make the stir fry sauce by mixing light and dark soy sauce, sugar, salt, vinegar, Shaoxing wine and white pepper in a bowl.
Chicken - Add chicken, garlic powder, chilli powder. Salt and corn starch to a bowl. Mix well and set aside for 10 minutes. Heat oil in a large wok on high heat. Add chicken and stir-fry on high for approximately 6 minutes until just cooked. Remove and set aside.
Heat another tablespoon oil in the wok on high. Add onion and carrot and stir fry for 30 seconds until glazed and starting to caramelize. Add garlic and stir fry for a few seconds until fragrant. Add peas, mushroom and capsicum. Toss and stir fry for 30 seconds.
Add rice and mix well. Push rice to the side of the wok and add the whisked egg in the gap. Cook for a few seconds, then push and toss the egg with a wooden/metal turner, slowly mixing it into the rice until the rice takes on a yellow hue.
Drain all the liquid from the chicken. Add the cooked chicken and sauce to the rice and mix well. Tossing constantly, stir fry for a minute until everything is heated through.
Add spring onion and lettuce. Toss to mix well and stir fry for a further 30 seconds until greens are just glazed.
Remove from heat. Rest for a couple of minutes and serve hot.