In a large mixing bowl, cream together ½ cup softened unsalted butter and 8 oz softened cream cheese until smooth and fluffy. Add 1 egg and 1 tsp vanilla extract, mixing until just incorporated. Gradually blend in 1 box of white cake mix until the dough is thick.

Gently fold in ¼ cup of colorful sprinkles. Cover the bowl with plastic wrap and refrigerate for at least 1 hour.

Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper. Scoop rounded tablespoons of chilled dough, rolling them into balls.

Roll each cookie dough ball in a mixture of confectioner's sugar and additional sprinkles before baking.

Arrange the cookie balls on the baking sheet, spaced 2 inches apart. Bake for 8-10 minutes until just set and lightly golden around the edges.

Let the cookies cool on the baking sheet for 2 minutes, then transfer to a wire rack to cool completely.