Heat oven to 350°F. Beat butter, granulated sugar, brown sugar and vanilla in large bowl on medium speed of mixer until creamy. Add eggs; beat well. Stir together flour, cocoa, baking soda and salt; gradually add to butter mixture, beating until well blended.
Drop dough by scant 1/4 cupfuls onto ungreased cookie sheet, about 3 inches apart. Shape into balls. Insert wooden stick about halfway into center of each. Flatten slightly.
Bake 10 to 12 minutes or until set. Cool 3 minutes; carefully remove from cookie sheet to wire rack. Cool completely.
Decorate as desired with decorating icing. Makes about 18 (3-1/2 inch) cookies.