Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper.

In a large mixing bowl, combine the cake mix, peanut butter, Cool Whip, egg, and vanilla extract. Mix until a soft, sticky dough forms.

Chill the dough for 20 minutes to make it easier to handle.

Scoop about 1 tablespoon of dough and roll it into a ball.

Coat each dough ball generously in powdered sugar.

Arrange the cookies about 2 inches apart on the prepared baking sheets.

Bake for 10–12 minutes, or until the cookies are puffed and lightly set around the edges.

Remove from the oven and immediately press one chocolate kiss into the center of each cookie.

Let the cookies cool on the baking sheet for 5 minutes, then transfer them to a wire rack to cool completely.