In a large bowl, add the chicken, garlic, a crack of freshly ground black pepper, black peppercorns, palm sugar, rice vinegar, dark soy sauce, regular soy sauce and ½ cup (120ml) of filtered water. Toss to evenly combine and then add the bay leaves.
Cover the bowl with plastic wrap and marinate in the refrigerator for 2 hours but ideally overnight.
Heat a large enameled cast iron braiser or Dutch oven over medium-high and drizzle with enough oil to coat the bottom of the pan.
In batches, remove the marinated chicken from the marinade and transfer into the heated pan. Do not discard the marinade as this will become the sauce. Cook for 2-3 minutes per side to sear and brown the skin. Remove onto a baking sheet and set aside.
Into the now-empty braiser or Dutch oven, pour in all of the marinade and heat over medium-high. Nestle all of the seared chicken pieces into the sauce and bring to a boil.
As soon as the sauce reaches a boil, immediately reduce the heat to low, cover and simmer for 35 minutes.
Remove the lid to turn each piece of chicken over. Then, cover again and cook for an additional 25-35 minutes, occasionally turning the chicken pieces to thoroughly coat in the sauce.
To serve, spoon the sauce all over the chicken. Garnish with sliced green onions. Serve alongside rice and the pan sauce.
