Prepare the Chicken: Cut the boneless, skinless chicken thighs or breasts into bite-sized pieces. Set aside.
Make the Sauce: In a mixing bowl, whisk together the soy sauce, bourbon whiskey (if using), brown sugar, apple cider vinegar, chicken broth, minced garlic, ground ginger, and crushed red pepper flakes.
Cook the Chicken: Heat the olive oil in a large skillet or wok over medium-high heat. Add the chicken pieces and cook until they are browned and cooked through, about 5-7 minutes. Remove the chicken from the skillet and set aside.
Combine Chicken and Sauce: In the same skillet, pour in the sauce mixture and bring it to a simmer. Let it cook for about 5 minutes, stirring occasionally, until it starts to thicken slightly.
Thicken the Sauce: In a small bowl, mix the cornstarch and water to make a slurry. Add this slurry to the skillet and stir well. Continue to cook for another 2-3 minutes until the sauce has thickened to your desired consistency.
Finish the Dish: Return the cooked chicken to the skillet, stirring to coat the chicken pieces evenly with the sauce. Cook for an additional 2-3 minutes until the chicken is heated through.
Serve: Serve the bourbon chicken over cooked rice. Garnish with sliced green onions and sesame seeds for an extra touch of flavor and presentation.