From Serious Eats

Ingredients

For the Chicken:

• 600-700 grams chicken fillets, cut into 2-3 cm chunks
• 1/2 teaspoon kosher salt
• 1/4 teaspoon ground white pepper
• 1 teapsoon dark soy sauce
• 1 teaspoon Shaoxing wine - or sherry if not available
• 1/2 teaspoon sugar
• 1/2 teaspoon roasted sesame oil
• 1/2 teaspoon cornstarch

For the Stir-Fry:

• 1 tablespoon dark soy sauce
• 1 tablespoon Shaoxing wine
• 1 tablespoon distilled white vinegar
• 2 tablespoons homemade or store-bought low-sodium chicken stock
• 1 tablespoon sugar
• 1 teaspoon roasted sesame oil
• 2 teaspoons cornstarch
• 3 tablespoons vegetable, peanut, or canola oil, divided
• 1 large red capsicum, cut into 2 cm dice
• 1 large green capsicum, cut into 2 cm dice
• 2 stalks celery, cut into 2 cm dice
• 1/2 cup roasted peanuts
• 2 teaspoons minced fresh garlic (about 2 medium cloves)
• 2 teaspoons minced fresh ginger
• 1 spring onion, white and light green parts only, finely minced
• 8 small dried red Chinese or Arbol chilies - if you don't have these a pinch of cayenne pepper will suffice

Method

1. For the Chicken: Combine chicken, salt, pepper, soy sauce, wine, sugar, sesame oil, and cornstarch in a medium bowl and toss to coat. Set aside for 20 minutes.
2. For the Stir-Fry: Combine soy sauce, wine, vinegar, chicken stock, sugar, sesame oil, and cornstarch in a small bowl and whisk together until homogenous. Set aside.
3. Heat 1 tablespoon oil in a wok over high heat until smoking. Add chicken, spread into a single layer, and cook without moving until lightly browned, about 1 minute. Continue cooking, tossing and stirring frequently, until the exterior is opaque but chicken is still slightly raw in the center, about 2 minute longer. Transfer to a clean bowl and set aside.
4. Wipe out wok and heat remaining 2 tablespoons oil over high heat until smoking. Add bell peppers and celery and cook, stirring and tossing occasionally, until brightly colored and browned in spots, about 1 minute. Add peanuts and toss to combine.
5. Push vegetables up side of wok to clear a space in the center. Add garlic, ginger, scallions, and dried chilies and cook, stirring, until fragrant, about 30 seconds. Return chicken to wok and toss to combine. Stir sauce and add to wok. Cook, tossing, until sauce thickens and coats ingredients and chicken is cooked through, about 1 minute longer. Serve immediately.