Combine graham cracker crumbs, melted Spread and sugar in medium bowl; press into 13 x 9-inch glass or ceramic baking dish.
Microwave chocolate chips, 2 cups marshmallows and milk in small microwave-safe bowl at HIGH 4 minutes or until completely melted, stirring once. Cool 10 minutes, then stir in remaining 2 cups marshmallows. Spread over crust; freeze 1 hour or until firm.
Sprinkle crumbled graham crackers over chocolate layer. With scissors, cut carton from Breyers® Chocolate Ice Cream. Arrange Ice Cream on its side, then cut crosswise into 4 slices. Arrange slices in baking dish, pressing to form an even layer. Cover and freeze 4 hours or overnight.
Frost with whipped topping just before serving. Sprinkle, if desired, with additional graham cracker crumbs.