In a large bowl, combine the chicken thighs, soy sauce, oyster sauce, and crushed garlic. Mix well. Cover with aluminum foil and marinate the chicken in the refrigerator for at least 1 hour.
Heat a large skillet over medium-high heat. Add the vegetable oil.
Once the vegetable oil is hot, begin to pan-fry the marinated chicken thighs for 2-3 minutes per side.
Add the remaining marinade to the skillet along with the water. Bring everything to a boil.
Once the mixture is boiling, add the dried bay leaves and whole peppercorns. Cover and let the mixture simmer over medium-low heat for approximately 30 minutes or until the chicken is tender.
After 30 minutes, add the vinegar, sugar, and salt. Stir and cook for 10 minutes. When the chicken thighs register as 165 degrees on an instant-read thermometer, the chicken is cooked through.
Serve immediately over a bed of plain rice or in a bowl with the remaining sauce from the marinade. Enjoy!
Marinating the chicken adds flavor. The longer the chicken marinates, the more flavorful it will be.
Filipino soy sauce or dark soy sauce is best for chicken adobo; however, any soy sauce may be used. If you're using a lighter soy sauce, your chicken adobo may not be as flavorful.