Mix together cream cheese and butter until combined.
Next, add in egg and vanilla in the mixing bowl and mix with butter/cream cheese mixture until combined.
Add in the cake mix. (Optional: Refrigerate for 30 minutes for a dough that's easier to work with if desired.)
Pour powdered sugar in to a small bowl for rolling.
Roll about a teaspoon of dough into balls, and roll into powdered sugar, placing them on to a greased cookie sheet or a cookie sheet covered with parchment paper, about 2 inches apart.
Bake at 350 for 12 minutes. Remove cookies from sheet and place on cooling rack. Allow cookies to cool.