Slice the chicken: Cut boneless, skinless chicken breast against the grain into thin 1/4-inch slices or bite-sized pieces. Pat dry with paper towels.

Optional Baking Soda Tenderization: In a medium bowl, combine the sliced chicken with baking soda (if using). Mix well and let sit for 10-15 minutes. *Important:* If using baking soda, rinse the chicken thoroughly under cold running water to remove all baking soda, then pat very dry with paper towels. Return chicken to a clean bowl.

Prepare the Velveting Marinade: To the bowl with the chicken, add cornstarch, egg white, soy sauce, Shaoxing wine, sesame oil, and water or broth. Mix thoroughly until the chicken is well coated and the marinade is mostly absorbed.

Marinate: Let the chicken marinate for at least 20-30 minutes at room temperature, or up to 2 hours in the refrigerator for deeper flavor and tenderization.

Cook the Chicken: Heat 2 tablespoons of vegetable oil in a wok or large skillet over medium-high heat until shimmering. Add the marinated chicken in a single layer, ensuring not to overcrowd the pan (cook in batches if needed). Stir-fry for 1-3 minutes until just cooked through and opaque on the outside but still very tender. Do not overcook, as this will toughen the chicken.

Remove and Use: Remove the velveted chicken from the pan and set aside. It's now ready to be added back into your stir-fry, soup, or other dish during the final stages of cooking.