In a mixing bowl, beat together the butter, vanilla, egg, and cream cheese until the mixture is light and fluffy.

Gradually add the cake mix and blend until fully incorporated.

Chill the dough in the refrigerator for 30 minutes to 1 hour.

Scoop out dough and roll into small balls. Roll each ball in holiday sprinkles and then coat thoroughly in powdered sugar.

Place the coated dough balls on a baking sheet and bake at 350°F for 10–12 minutes, or until the edges are lightly golden.

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