Sweet, sour, salty, and spicy, kung pao chicken is a dish that originates from the Sichuan Province of central-western China. The most important ingredient of Kung Pao chicken is the Sichuan peppercorn. Curious that by the time the dish became a hit in America, the recipe rarely included Sichuan peppercorns. Perhaps, it’s the unavailability. But if you have access to Sichuan peppercorns and you want to cook kung pao chicken at home, I suggest that you not underestimate the wonderful flavors and aroma that only Sichuan peppercorns can impart to this dish.
Kung pao chicken is meant to cook within a few minutes and very high heat throughout the cooking is essential. Place the diced chicken in a bowl. Mix all the ingredients for the marinade and pour into the bowl. Mix well. Allow to sit in the fridge for about 30 minutes.
Heat the cooking oil in a wok. When smoking, add the Sichuan peppercorns and chilis. Stir fry until fragrant. Add the marinated chicken, moving the pieces around to separate them (depending on the size of your work, you may have to do this in batches). Cook just until the chicken turns a light brown. Scoop everything out chicken, chilis, and peppercorns, and transfer to a strainer.
Pour off the oil, leaving only about three tablespoonfuls. Reheat until smoking. Add the garlic and ginger; stir fry for a few seconds. Add the peanuts (and carrot and bell pepper, if using) and stir fry until it smells roasted. Mix all the ingredients for the sauce, and pour into the wok, stirring fast. Return the chicken, chilis, and Sichuan peppercorns to the wok. Toss and stir to coat each piece of chicken with sauce. Turn off the heat. Transfer the cooked kung pao chicken to a platter, garnish with chopped greens, and serve at once.