To infuse the chicken with flavor and tenderize it, it's important to marinate it beforehand. In a bowl, combine the soy sauce, Chinese rice wine or dry sherry, and cornstarch. Mix the marinade ingredients until well combined. Add the chicken pieces to the marinade and toss them to coat evenly. Let the chicken marinate for at least 20 minutes to allow the flavors to develop.

While the chicken is marinating, it's time to prepare the garlic mixture. In a small bowl, combine the minced garlic, minced ginger, sliced green onions, and chopped dried red chilies (if using). Set the garlic mixture aside until ready to use.

Next, it's time to prepare the flavorful sauce that will coat the garlic chicken. In a separate bowl, whisk together the soy sauce, oyster sauce, hoisin sauce, Chinese rice wine or dry sherry, sugar, and sesame oil until well combined. Set the sauce aside until needed.

Once the chicken has finished marinating, it's time to cook the garlic chicken. Heat a wok or a large skillet over medium-high heat. Add the vegetable oil and swirl it around to coat the surface of the pan.

When the oil is hot, carefully add the marinated chicken to the pan. Stir-fry the chicken for about 5-7 minutes or until it is cooked through and no longer pink in the center. The cooking time may vary depending on the size of the chicken pieces. Use a spatula or tongs to move the chicken around in the pan, ensuring it cooks evenly.

Once the chicken is cooked, transfer it to a plate and set it aside. In the same pan, add a little more vegetable oil if needed. Heat the oil over medium heat. Add the minced garlic, minced ginger, sliced green onions, and chopped dried red chilies (if using) to the pan. Stir-fry the garlic mixture for about 1-2 minutes, or until fragrant and the garlic turns golden brown. Be careful not to burn the garlic, as it can become bitter.

Once the garlic mixture is fragrant and golden brown, return the cooked chicken to the pan. Pour the prepared sauce over the chicken and garlic mixture, stirring well to coat everything evenly. Continue stir-frying for an additional 1-2 minutes, allowing the chicken and garlic to absorb the flavors of the sauce.

Chinese garlic chicken is best served immediately while it's hot and flavorful. Garnish the dish with additional sliced green onions for freshness and color. Serve the garlic chicken over steamed rice or noodles for a complete and satisfying meal.