In a large mixing bowl, combine the chicken with soy sauce, vinegar, crushed garlic, bay leaves, and whole black peppercorns. Stir to ensure the chicken is well coated. Cover and refrigerate for at least 30 minutes, or up to 2 hours, to let the flavors infuse deeply into the meat.
Heat the oil in a wide, deep skillet or heavy-bottomed pot over medium-high heat. Once hot, add the marinated chicken pieces and sear them until golden on all sides. This caramelization step enhances the savory depth of the final dish. Transfer the seared chicken to a plate and set aside.
In the same pan, use the remaining oil to sauté the leftover garlic from the marinade. If you skipped the marinating step, mince 4–5 fresh cloves and sauté until golden and aromatic, about 1 to 2 minutes.
Return the browned chicken to the pot. Pour in the reserved marinade, then stir in the brown sugar. Add 1 cup of water or chicken broth if you prefer a more generous amount of sauce.
Raise the heat to medium-high and bring the pot to a gentle boil. Avoid stirring immediately after adding the vinegar—let it boil undisturbed for a minute or two to mellow its sharpness.
Lower the heat, cover the pot, and allow the dish to simmer for 30 to 40 minutes, stirring occasionally. The chicken should become tender, and the sauce will start to reduce naturally as it cooks.
Uncover the pot during the last 10 to 15 minutes of cooking to let the sauce further reduce. This step deepens the flavor and thickens the consistency to a glossy glaze that clings to the chicken.
Taste the sauce. Add a bit more sugar for a sweeter note or a pinch of salt if needed to enhance the savory undertones. Balance is key.
Dish out the sweet adobo chicken hot over steamed white rice. Be generous with the sauce—it’s especially delicious spooned over the rice.