Marinate the chicken: Toss the chicken pieces with 1 tablespoon soy sauce, the sherry, and 1 tablespoon cornstarch until every piece is coated. Let it sit for 15 minutes while you prep everything else.

Mix the kung pao sauce: In a small bowl, whisk together the 3 tablespoons soy sauce, black vinegar, brown sugar, hoisin, sesame oil, 2 teaspoons cornstarch, and chicken broth until the cornstarch fully dissolves. Set it right next to the stove.

Sear the chicken: Heat the vegetable oil in a large skillet or wok over medium-high heat until it shimmers. Add the chicken in a single layer and let it sit undisturbed for 2 minutes to brown, then stir and cook another 3-4 minutes until golden all over and cooked to 165°F on an instant-read thermometer. Move it to a plate.

Toast the chiles and aromatics: Turn the heat down to medium. Add the dried chiles and stir for 20-30 seconds, just until you can smell them, well before they darken. Add the garlic, ginger, the white pieces of green onion, and the ground Sichuan peppercorns, if using, and stir 30 seconds more. The peppercorns go in here rather than into shimmering oil, since ground spice has no husk to protect it and scorches into bitterness in seconds.

Sauce it: Return the chicken and any juices to the pan. Give the sauce a quick re-whisk and pour it in. Cook for 1-2 minutes, stirring constantly, until it thickens into a glossy glaze that coats every piece of chicken.

Finish with peanuts: Take the pan off the heat and fold in the roasted peanuts and the green tops of the onions. Adding them last keeps the peanuts crunchy and the onions bright.

Serve: Spoon over the cooked white rice while everything is still hot.