In a bowl, marinate chicken with soy sauce, vinegar, minced garlic, and bay leaves for at least 30 minutes (or overnight for deeper flavor).
Heat 1 tbsp oil in a skillet over medium heat. Sear marinated chicken (reserve the marinade) until lightly browned on both sides.
Remove chicken and set aside. In the same pan, add remaining oil, garlic, and onion. Sauté until soft and golden.
Return chicken to the pan. Add reserved marinade, water, brown sugar, and black pepper. Stir to combine.
Bring to a boil, then lower heat. Cover and simmer for 30–35 minutes, until chicken is tender and sauce thickens.
Remove lid in the last 5 minutes if you want the sauce to reduce further.
Garnish with sliced green onions.
Serve hot with rice, Cucumber Salad, or Garlic Naan.