Preheat oven to 350 degrees.
In a medium saucepan, combine all sauce ingredients and cook over medium heat, stirring often for about 20-25 minutes, until sauce is thickened.
While sauce is heating, remove all skin from chicken thighs. Place thighs in a 13 x 9 inch Pyrex dish or pan lined with foil.
Set aside 2 cups barbecue sauce for later. Pour remaining sauce over chicken. Cover with foil and bake for 45 minutes.
To finish off the chicken, broil or cook on the grill.
To broil: Place chicken on a foil-lined baking sheet. Cover chicken with half the remaining sauce. Broil for about 5 minutes until chicken is caramelized. Turn over, spread with remaining sauce, and broil for about 5 more minutes until caramelized.
To grill: Prepare grill to cook at medium heat. Brush chicken with barbecue sauce and cook until caramelized, about 5 minutes. Turn chicken over, brush with more sauce and cook about 5 more minutes until caramelized.