S'mores 'Sushi'

Spread graham crumbs onto bottom of 8-inch square pan sprayed with cooking spray. Microwave butter and 2 oz. semi-sweet chocolate in medium microwaveable bowl on HIGH 1 min. or until butter is melted; stir until chocolate is completely melted and mixture is well blended. Add 2-1/2 cups marshmallows; mix lightly. Microwave 1 min. or until marshmallows are completely melted and mixture is well blended when stirred. Add cereal and cocoa powder; mix well.

Press cereal mixture into even layer over graham crumbs in pan. Let stand 15 min. or until cereal mixture is firm but still pliable.

Remove cereal mixture from pan; place on cutting board. Cut crosswise in half. Arrange single row of half the remaining marshmallows lengthwise down centre of each rectangle; fold both long sides of each rectangle to centre of rectangle then press to form log. Tap any remaining graham crumbs from pan onto cutting board. Roll logs, 1 at a time, in crumbs. Cut each log into 8 slices to resemble sushi.

Microwave Cool Whip and remaining semi-sweet chocolate in microwaveable bowl 1 to 1-1/2 min. or until chocolate is completely melted and mixture is well blended, stirring every minute. Serve as a dipping sauce with the "sushi."