In a bowl, combine the chicken pieces with 2 tablespoons of cornstarch, 1 teaspoon soy sauce, and 1 tablespoon of rice wine. Stir to coat the chicken evenly and let it marinate for about 10-15 minutes. This helps tenderize the chicken and gives it a light coating.
Prepare the Sauce:
In a small bowl, whisk together the soy sauce, oyster sauce, rice vinegar, hoisin sauce (if using), sesame oil, brown sugar, and chicken broth. Stir until the sugar is dissolved. Set aside.
Cook the Chicken:
Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium-high heat. Once hot, add the marinated chicken pieces in a single layer (do this in batches if necessary to avoid overcrowding). Cook the chicken for 3-5 minutes, stirring occasionally, until it is golden brown and cooked through. Remove the chicken from the skillet and set it aside.
Stir-Fry the Vegetables:
In the same skillet, add the sliced onions, bell peppers, garlic, and ginger (if using). Stir-fry for 2-3 minutes, until the vegetables begin to soften but still have a bit of crunch. Add the cashews and cook for another 1-2 minutes.
Combine and Cook the Sauce:
Return the cooked chicken to the skillet with the vegetables. Stir in the sauce mixture. Bring everything to a simmer over medium heat, and cook for about 2-3 minutes, allowing the sauce to thicken. If you prefer a thicker sauce, add the cornstarch slurry (1 teaspoon cornstarch mixed with 2 tablespoons water) and cook for another minute until the sauce is glossy and thickened.
Garnish and Serve:
Once everything is well-coated in the sauce, remove from heat and garnish with chopped green onions. Serve the Cashew Chicken hot, with steamed rice or noodles on the side.
