- 1 (15.25 ounce) package yellow cake mix
- 1 cup water
- 1/3 cup vegetable oil
- 1 (8 ounce) container frozen whipped topping, thawed
- 20 chocolate cream-filled sandwich cookies, crushed
- Beat cake mix, water, and vegetable oil together in a bowl with an electric mixer on medium speed until smooth. Fold whipped topping and crushed cookies into batter.
- Cover the bowl with plastic wrap and refrigerate until cookies are softened and mousse firms, about 24 hours.