Heat the oven to 400°F. Pat thighs dry, rub with oil, salt, paprika and pepper and place skin-side up on a rack over a rimmed baking sheet.
Bake for 30 minutes. Meanwhile, combine ketchup, molasses, vinegar, mustard, Worcestershire, garlic powder and water in a small saucepan.
Simmer the sauce gently for 4 to 5 minutes, stirring, until lightly thickened. Transfer half to a clean bowl for serving and use the rest only for brushing during cooking.
Brush chicken lightly with cooking sauce and bake for 10 minutes. Brush once more and bake for 5 to 10 minutes until sticky, with the thickest meat at 175 to 185°F; discard any cooking sauce left on the brush or in its bowl.
Rest uncovered for 5 minutes and serve with the reserved clean sauce spooned over the meat.