Pat and Season the Chicken: Place the 4 chicken thighs on a cutting board and pat each piece thoroughly dry with paper towels, pressing firmly on both the skin side and the underside. Removing surface moisture from the skin is a critical step: dry skin makes direct contact with the hot pan surface, which drives the Maillard reaction and produces deep browning rather than steaming. Set the dried thighs aside on the cutting board while the pan heats.
Sear the Chicken Thighs: Heat 1 tablespoon of neutral cooking oil in a 12-inch heavy-bottomed skillet over medium-high heat for 2 minutes until the oil shimmers and moves freely across the pan surface. Place the chicken thighs skin-side down in the pan, pressing each one flat with tongs to maximize skin contact, and sear for 5 minutes without moving them until the skin is deep golden brown and pulls away from the pan cleanly.
Flip and Sear the Underside: Flip each chicken thigh using tongs and sear the underside for 3 minutes until the flesh side is opaque and lightly browned. Transfer the seared thighs to a plate and set aside. Do not discard the rendered fat left in the pan, as it forms the flavor base for the braising liquid.
Build the Braising Liquid: With the skillet still over medium heat, add the crushed garlic cloves directly to the rendered fat and cook for 1 minute, stirring with a wooden spoon, until the garlic is fragrant and lightly golden at the edges. Pour in the 80ml / 1/3 cup of white cane vinegar, 60ml / 1/4 cup of soy sauce, and 120ml / 1/2 cup of water. Add the 3 bay leaves and 1 teaspoon of whole black peppercorns. Stir once to combine all ingredients.
Return Chicken and Braise: Nestle the seared chicken thighs back into the skillet skin-side up, ensuring each piece sits partially submerged in the braising liquid. Bring the liquid to a full boil over medium-high heat, then immediately reduce the heat to medium-low and cover the skillet with a tight-fitting lid. Braise for 20 minutes until the chicken is fully cooked through, the meat pulls slightly away from the bone at the joint, and an instant-read thermometer inserted at the thickest part reads 74°C / 165°F.
Reduce the Sauce: Remove the lid and increase the heat to medium-high. Cook uncovered for 10 minutes, turning the chicken thighs once at the 5-minute mark, until the braising liquid reduces by approximately half and coats the back of a spoon in a thin, glossy layer. If using sugar, stir in 1 teaspoon during the final 2 minutes of reduction. Remove and discard the bay leaves before serving.
