Heat a skillet over medium-high heat. Add chicken thighs skin-side down and cook for 3-4 minutes per side until golden brown. Transfer the chicken to the crockpot. The chicken does not need to be fully cooked at this stage.
2 lbs chicken thighs
In the same skillet, add smashed garlic and sliced onion. Cook for 1-2 minutes until fragrant. Pour in soy sauce, vinegar, water or broth, and brown sugar if using. Stir well, scraping up browned bits from the pan.
0.5 cup soy sauce, 0.5 cup vinegar, 0.5 cup water, 2 tbsp brown sugar, 8 cloves garlic, 1 medium onion
Pour the sauce over the chicken in the crockpot. Add bay leaves and black peppercorns. Cover and cook on low for 4 to 6 hours, until chicken reaches an internal temperature of 165°F and the meat pulls away from the bone easily.
3 leaves bay leaves, 1 tsp black peppercorns
During the last 30 minutes of cooking, remove the crockpot lid to thicken the sauce, or transfer the chicken to a plate and simmer the sauce on the stove for 5-7 minutes until syrupy.
Remove bay leaves and taste the sauce. Adjust by adding more vinegar if too mild, more sugar if too sour, or more soy if too bland. Stir gently to coat the chicken and serve over rice.
0.5 cup soy sauce, 0.5 cup vinegar, 2 tbsp brown sugar
