Prepare the Chicken: Slice the chicken into thin bite size pieces. Place them in a bowl with cornstarch, baking soda, Shaoxing wine, and dark soy sauce. Mix well until every piece looks coated. Let it rest for about fifteen minutes. This step keeps the chicken tender during high heat cooking.
Mix the Sauce: Grab a small bowl and combine brown sugar, rice vinegar, soy sauce, oyster sauce, soy sauce, and sesame oil. Stir until the sugar dissolves fully. Set this aside so it stays ready when the pan heats up.
Heat the Pan: Place a large wok skillet over medium high heat. Add peanut oil and let it warm until it shimmers. A hot pan helps everything cook fast without turning soggy.
Cook the Chicken: Add the marinated chicken in a single layer. Let it cook without moving for a minute so it browns nicely. Stir and cook until the pieces turn just cooked through. Remove the chicken from the pan and set aside.
Build the Flavor Base: Drop garlic and ginger into the same pan. Stir quickly so they release aroma without burning. Add onion slices and cook until they soften slightly.
Add the Vegetables: Toss in mushrooms and bell pepper. Stir fry until the mushrooms shrink and release moisture. The pan should look glossy and fragrant at this point.
Bring Everything Together: Return the chicken to the pan. Pour in the prepared sauce and toss well so everything gets coated. Let it simmer briefly until the sauce thickens and clings to the chicken and vegetables.
Finish and Serve: Sprinkle green onions over the top and give one final toss. Turn off the heat and serve right away while everything stays hot and saucy.
