Preheat oven to 300 degrees Fahrenheit with the rack in the lower-middle section.
Whisk 1 cup water, 1 cup soy sauce, 1/4 cup sherry, 2 Tbsp sugar, 2 Tbsp molasses and 1 Tbsp vinegar together in a 12-inch skillet.
Arrange chicken, skin side down, in the soy mixture and nestle ginger and garlic between the chicken.
Bring mixture to a simmer over medium heat, around 5 minutes.
Transfer skillet, or Dutch oven, uncovered into the oven and then cook for 30 minutes.
Carefully flip chicken in the skillet and then continue to cook for 20-30 additional minutes, making sure the chicken temps at 165 degrees.
Using tongs, transfer the chicken thighs to a platter, being careful to not break or tear the crispy skin.
Pour cooking liquid through a fine-mesh strainer and then collect into a bowl, or into a fat separator and let settle for 5 minutes.
Turn the broiler on in the oven.
Whisk the cornstarch and the remaining 1/2 cup water together in a bowl.
Pour 1 cup defatted cooking liquid into the now-empty skillet and then bring to a simmer over medium heat.
Whisk cornstarch into the simmering liquid and simmer until thickened, about 1 minute.
Pour sauce into a bowl and then set aside for serving.
Return the chicken skin side up to the empty skillet and place in the oven under the broiler until well browned. This should not take more than 3-4 minutes.
Serve with sauce separately with steamed vegetables and rice or quinoa.