Preheat oven to 350 degrees F. Spray baking sheets with cooking spray or line with parchment.
In a large bowl, use a wooden spoon to stir together cake mix, whipped topping, and egg until a thick dough forms.
Place sugar in a separate bowl.
Use a spoon to scoop about 1 tablespoon of cookie dough into the sugar at a time. Roll the dough around in the sugar to coat, gently roll between your hands to form a ball, and place sugar-coated dough balls onto prepared baking sheets.
Bake at 350 degrees F for 10-15 minutes, or until just starting to turn golden around the edges. The centers will still be soft, and that’s good – they firm up when they cool, and they will stay soft and chewy!
Use this formula to try other flavor combinations by mixing up the type of cake mix you use -- chocolate, vanilla, strawberry, or red velvet -- for example!