In a large mixing bowl, beat together softened unsalted butter, softened cream cheese, vanilla extract, and a large egg until fluffy and well-combined.

Gradually add in the yellow cake mix to the wet ingredients, mixing on low speed until fully combined and smooth.

Cover the bowl with plastic wrap and refrigerate the dough for 30 minutes to 1 hour.

Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

Once the dough is chilled, roll the dough into 1-inch balls, and optionally roll in colorful sprinkles before coating with powdered sugar.

Place the sugared dough balls on the prepared baking sheet, baking for 10-12 minutes until edges are lightly golden.

Allow cookies to cool on the baking sheet for about 5 minutes before transferring to a wire rack to cool completely.