Step 1

Stir 1 (15.25-ounce) box cake mix, 8 ounces thawed frozen whipped topping, 1 large egg, and 1 tablespoon vanilla extract together in a large bowl with a flexible spatula until fully incorporated, 4 to 5 minutes. The mixture will be thick.

Step 2

Cover and refrigerate for 30 minutes. Meanwhile, heat the oven to 350ºF. Line 2 baking sheets with parchment paper. Place 1/2 cup powdered sugar in a medium bowl.

Step 3

Portion and coat one cookie at a time: Scoop out a heaping tablespoon of the dough (it may be a little sticky) and drop into the powdered sugar. Toss with your hands until fully coated, then place on the baking sheet, spacing them evenly apart, 12 per sheet.

Step 4

Bake for 8 minutes. Rotate the baking sheets from bottom to top and from front to back. Bake until the powdered sugar has cracked and cookies are browned around the edges, about 8 minutes more. Let cool for 5 minutes on the baking sheets. Transfer the cookies to a wire rack and let cool completely.