In small bowl, whisk 2 cups of the flour, the baking powder and salt. In large bowl, beat butter and sugar until smooth, 1 minute. Beat in egg, egg white and peppermint. On low, beat in flour mixture. Remove half of dough to bowl; stir in remaining 1 tablespoon flour and tint dough pink with red food coloring. Knead cocoa into second half of dough. Flatten each piece into 8-inch disk; wrap each in plastic. Refrigerate 2 hours.