Velvet the Chicken: In a bowl, combine chicken pieces with egg white, cornstarch, soy sauce, Shaoxing wine (if using), and sesame oil (if using). Mix well until chicken is fully coated. Let it marinate for at least 15 minutes at room temperature, or up to 30 minutes in the refrigerator.

Prepare the Sauce: In a small bowl, whisk together chicken broth, soy sauce, oyster sauce, cornstarch, sugar, and white pepper. Set aside.

Cook Chicken: Heat 1 tablespoon of vegetable oil in a large wok or skillet over high heat until shimmering. Add the velveted chicken in a single layer (cook in batches if necessary to avoid overcrowding) and stir-fry for 2-3 minutes until cooked through and lightly golden. Remove chicken from the wok and set aside.

Stir-Fry Vegetables: Add the remaining 1 tablespoon of vegetable oil to the wok. Add minced ginger and garlic and stir-fry for 30 seconds until fragrant.

Add broccoli florets, bell pepper, and julienned carrots. Stir-fry for 3-5 minutes until vegetables are crisp-tender. Add water chestnuts if using.

Combine and Sauce: Return the cooked chicken to the wok with the vegetables. Give the prepared sauce a quick whisk (as cornstarch settles) and pour it over the chicken and vegetables.

Stir constantly until the sauce thickens and coats everything, about 1-2 minutes.

Garnish with sliced green onions and serve immediately with steamed rice.