preheat oven to 375°. Line a 15 x 10" baking pan with parchment paper or foil; set aside. Remove and discard skin from chicken. Arrange chicken, boned side up in the prepared baking pan. Bake, uncovered for 35 minutes.
Meanwhile, for sauce, in a large pan cook onions, garlic, and salt in butter over medium low heat for 10 to 15 minutes or until tender, stirring occasionally. Add Paprika, chili powder, crushed red pepper, and black pepper; cook and stir for one minute more. Add the water, vinegar, Brown sugar, and Worcestershire sauce; bring to boiling. Whisk in tomato paste and molasses until smooth. Boil gently, uncovered, for 15 to 20 minutes or until sauce is thickened and reduced to about 4 cups, stirring occasionally.
Turn chicken bone sides down. Brush about 1 cup of the sauce over the chicken. Bake for 10 to 20 minutes more or until chicken is no longer pink. Reheat some of the remaining sauce; pass with the chicken. Store any remaining sauce in an airtight container in the refrigerator for up to one week. Makes six servings.