1Heat oven to 350°F (325°F for dark or nonstick pan). Spray bottom and sides of 13x9-inch pan with baking spray with flour.
2Make and bake cake mix as directed on box, using water, oil and eggs. Cool completely in pan on cooling rack. Crumble cake with fork.
3In each of 24 (4-oz) glass jars or cups, place 1 small scoop of ice cream. Layer with crumbled cake and half of the cookie pieces. Top with remaining ice cream, a dollop of whipped topping and remaining cookie pieces. Serve immediately or freeze until serving time.