To prepare the chicken, pat the chicken dry with paper towels. Using kitchen shears, remove the backbone to spatchcock the chicken. Cut a small notch into the breastbone and flatten the chicken.
To sear the chicken, in a large pan over high heat, add the cooking oil. Place the chicken skin-side down and sear for about 1 minute, or until lightly golden. Flip and sear the other side for another minute.
To make the braising liquid, add the ginger and scallions to the pan. Pour in the water, soy sauce, dark soy sauce, and Shaoxing wine. Add the rock sugar, cinnamon stick, star anise, and bay leaves.
To braise the chicken, cover the pan and cook over medium-low heat for about 20 minutes, or until the chicken is fully cooked and the thickest part reaches an internal temperature of 165°F (74°C).
To reduce the sauce, remove the lid and increase the heat to high. Cook for about 2 minutes, continuously spooning the sauce over the chicken as it reduces.
To serve, transfer the chicken to a cutting board and let it rest for a few minutes. Slice or chop into serving pieces and drizzle with the reduced sauce before serving.