Spread the cake mix in a thin, even layer on a parchment-lined baking sheet. Bake at 350F for 5 minutes to heat treat it. Let it cool completely before moving on, this step matters for both safety and texture.

Once cooled, fold the cake mix into the Cool Whip until fully combined.

Heat the chocolate icing in the microwave for just a few seconds, enough to loosen it up for spreading. You want it soft, not hot.

Spread the icing over the top of the cool whip mixture.

Cover and refrigerate until ready to serve.