Stir together brownie mix and cocoa in large bowl. Add water, syrup, egg and oil, beating until well blended. Refrigerate about 30 minutes or until firm enough to roll.
Heat oven to 350°F. Line cookie sheets with parchment paper or lightly grease. Shape dough into 42 equal balls (about 1 inch). Roll in sugar, if desired. Place on prepared cookie sheets.
Bake 8 to 10 minutes or until set. Cool 2 minutes; press a chocolate piece into center of each cookie. Slide parchment paper and cookies to wire rack or remove cookies from cookie sheet to wire rack. Cool completely.