Cut the chicken into one-inch chunks. Toss them with 2 tablespoons of cornstarch, salt, and pepper in a bowl until evenly coated. This will give the chicken a slight crisp as it cooks.
Heat 2 tablespoons of vegetable oil in a large skillet over medium-high heat. Fry half the chicken for about 3 minutes on each side, until golden. Remove from the skillet and cook the second batch with the remaining oil. Set the chicken aside.
Using the same skillet, lower the heat slightly and add the minced garlic. Cook for about 30 seconds, stirring constantly, until it becomes fragrant (be careful not to burn it).
Pour water, apple juice, bourbon, chicken broth, soy sauce, ketchup, apple cider vinegar, brown sugar, onion powder, ground ginger, and crushed red pepper flakes into the skillet. Stir well and bring the mixture to a gentle boil.
Return the cooked chicken to the skillet, ensuring all pieces are coated in the sauce. Simmer on low heat for 10–15 minutes, allowing the sauce to reduce and intensify in flavor.
Prepare a slurry by mixing the remaining tablespoon of cornstarch with a splash of cold water. Stir this mixture into the skillet until the sauce thickens to a glossy glaze.
Plate the bourbon chicken hot on top of steamed rice, noodles, or even roasted vegetables. Garnish with chopped green onions for a fresh pop of color.