Prepare the Oven
Preheat the oven to 350°F (175°C).
Line a baking sheet with parchment paper.
Make the Dough
Add the chocolate cake mix to a large bowl.
Add the thawed Cool Whip.
Crack in the egg.
Stir with a spatula until completely combined.
The dough will be thick and sticky.
Coat the Dough
Place powdered sugar into a small bowl.
Scoop about 1 tablespoon of dough.
Drop the dough into the powdered sugar.
Roll until completely coated.
Place on the prepared baking sheet, leaving about 2 inches between cookies.
Bake
Bake for 10–12 minutes.
The cookies should be set around the edges.
The centers should still look slightly soft.
Do not overbake.
Cool
Let the cookies cool on the baking sheet for 5 minutes.
Transfer them to a wire rack.
Cool completely before serving.