Combine sliced chicken with Shaoxing wine, sesame oil, cornflour, salt, white pepper and MSG if using. Mix well and set aside to marinate for at least 10 minutes.
Bring a pot of water to the boil. Add 1 tsp oil and blanch your vegetables for 1-2 minutes until just tender but still vibrant. Drain and set aside. (This technique keeps your vegetables bright and prevents them going soggy in the wok.)
Heat oil in a wok or large frying pan over high heat. Add the marinated chicken and cook until golden and cooked through. Remove and set aside.
Add a little more oil to the same pan. Cook onion until softened, then add the minced garlic and stir fry for 30 seconds until fragrant.
Return the chicken to the pan along with the blanched vegetables. Add oyster sauce, soy sauce and a pinch of sugar. Toss everything together.
Pour in the hot chicken stock and stir to combine. Add the cornflour slurry and cook for 1-2 minutes until the sauce thickens and coats everything beautifully.
Finish with a generous drizzle of sesame oil. Taste and adjust salt as needed. Serve immediately over steamed rice.