Preheat oven to 350F. Spray Cookie sheet with non-stick cooking spray.
In a large bowl, mix together 1 box lemon cake mix, 1 egg, and 1 (8 oz) tub of Cool Whip. The mix will be VERY fluffy. Just keep mixing until well combined.
Place ½–1 cup powdered sugar in a small bowl. Scoop the dough into small balls and roll each ball in the powdered sugar until fully coated. Place the coated dough balls onto the prepared baking sheet, about 2 inches apart.
Bake at 350F for 8 minutes or until very lightly golden around the edges. Let cool on the cookie sheet for a couple of minutes before removing to wire racks to cool completely.
Store at room temperature in airtight container. These are best eaten within a day or two of baking.
Notes
Feel free to substitute the boxed lemon cake mix with any other boxed cake mix.