In a large bowl, combine the garlic, soy sauce, water, vinegar, whole peppercorns, ground black pepper, dark brown sugar, and bay leaves.
Add the chicken to the bowl. Marinate for at least 30 minutes, or refrigerate overnight for best results.
In a large pan, heat the cooking oil over medium heat. Remove the chicken from the marinade, reserving the liquid, and fry the chicken until golden brown on all sides.
Pour the reserved marinade mixture back into the pan with the browned chicken and bring to a boil.
Reduce the heat to low, cover, and let it simmer for 15 minutes.
Flip the chicken to the other side and simmer for another 15 minutes until the chicken is completely cooked through and the sauce thickens.
Remove from heat, garnish with chopped green onions, and serve immediately over steamed rice.