Beat butter, sugars, and vanilla until creamy. Add eggs, beat well. Gradually add combined flour, cocoa, baking soda and salt; mix well. Stir in remaining ingredients.
Drop by rounded tablespoonfuls onto ungreased cookie sheets. Bake 9 to 10 minutes or until set. Cool 2 minutes on cookie sheet; remove to wire rack. Cool completely. Store tightly covered. Makes 4 dozen.