Velvet the Chicken: In a bowl, combine chicken pieces with 1 tablespoon cornstarch, egg white, baking soda, Shaoxing wine, and 1 tbsp soy sauce. Mix well and let marinate for at least 15 minutes, or up to 30 minutes in the refrigerator.

Prepare the Sauce: In a separate small bowl, whisk together 2 tablespoons soy sauce, dark soy sauce (if using), Chinkiang vinegar, sugar, sesame oil, 1 tablespoon cornstarch, and water/broth until smooth. Set aside.

Stir-fry Aromatics: Heat 1 tablespoon of vegetable oil in a large wok or skillet over medium-high heat. Add dried red chilies and Sichuan peppercorns. Stir-fry for 30 seconds to 1 minute until fragrant and chilies slightly darken (be careful not to burn). Remove chilies and peppercorns with a slotted spoon and set aside.

Cook Chicken: Add the remaining 1 tablespoon of vegetable oil to the wok. Increase heat to high. Add the marinated chicken in a single layer (cook in batches if necessary to avoid crowding). Cook for 3-4 minutes, turning occasionally, until golden brown and cooked through. Remove chicken from the wok and set aside with the chilies and peppercorns.

Build the Dish: Add minced garlic, grated ginger, and white parts of scallions to the wok. Stir-fry for 30 seconds until fragrant.

Combine and Serve: Return the cooked chicken, chilies, and Sichuan peppercorns to the wok. Give the prepared sauce a quick whisk (cornstarch settles) and pour it over the chicken. Stir quickly to coat everything evenly as the sauce thickens, about 1-2 minutes.

Stir in the roasted peanuts. Garnish with sliced green scallion parts and serve immediately with steamed white rice.