The Marination (Don't Skip This!)

Cut your chicken into 1-inch bite-sized chunks. Place them in a large zip-top bag with the cornstarch, soy sauce, Shaoxing wine, and brown sugar. Massage the bag to ensure every piece is coated. Let it chill in the fridge for at least 30 minutes, though a full day of marinating will yield the most tender results.

The Prep Work

While the chicken marinates, chop your bell peppers, zucchini, and scallions. Mince your garlic and ginger. This is a fast-moving recipe, so having your "mise en place" ready is essential.

The Sauce Assembly

In a small bowl or pitcher, whisk together the oyster sauce, soy sauce, sesame oil, garlic, ginger, and black pepper. Setting this aside now prevents you from scrambling once the pan is hot.

The Sizzle

Set a large sauté pan or wok over medium-high heat with vegetable or peanut oil. Once shimmering, add the chicken along with its marinade. Stir-fry for 3–4 minutes until the chicken is mostly cooked through.

The Veggie Toss

Add the red bell peppers, zucchini, and peanuts to the pan. Stir-fry for another 2 minutes. You want the vegetables to be lightly cooked but still retain a satisfying, firm crunch.

The Grand Finale

Pour in your prepared stir-fry sauce. Cook for about 2 minutes, stirring constantly, until the sauce thickens into a glossy glaze that coats every piece. Stir in the scallions at the very last second and serve immediately.