Preheat oven to 350 degrees F. Slice cookie dough 1/4 inch thick; arrange slices 2 inches apart on ungreased cookie sheets. In small bowl combine sugar and cinnamon. Generously sprinkle over dough slices. Bake for 9 to 11 minutes or until lightly browned. Cool 1 minute on cookie sheet. Remove cookies and cool completely on wire racks.
Spoon ice cream into large bowl. Let stand 10 minutes to soften slightly. Stir in coconut. Using an ice cream scoop, place some ice cream mixture onto flat sides of half of the cookies. Top with remaining cookies and press together gently. Place cornflakes in shallow dish; roll edges of sandwiches in cornflakes to coat ice cream. Immediately wrap each sandwich in plastic wrap and freeze 2 hours or until firm, or up to 1 month. Let stand 10 minutes at room temperature before serving to soften slightly. Makes about 14 sandwiches.