PREHEAT oven to 325º F. Foil-line 13 x 9-inch baking pan, allowing foil to reach up sides of pan. Grease foil.
COMBINE softened cookie dough and cocoa in large mixer bowl. This can be done with a mixer or with clean hands. Press dough into prepared pan.
BAKE for 15 to 20 minutes or until wooden pick inserted in center comes out clean. Cool completely in pan on wire rack. Carefully lift from pan using foil to serving platter. Carefully remove foil; return to platter.
FOR BORDER, gently stir in 1 tablespoon white frosting into chocolate frosting (do not overmix- need to keep some light brown streaks for wood affect). Frost a 1-inch border around the top edges and sides. An additional tablespoon of white frosting can be added if more highlights are needed.
WRITE your personalized back-to-school message on the cookie blackboard!
* 2 cups NESTLÉ® TOLL HOUSE® Refrigerated Chocolate Chip Tub Dough can be substituted for the bar dough.