Make the cookie dough. In a medium bowl, cream together the butter and cream cheese using a handheld electric mixer. Add the egg and vanilla and mix until well combined. Add the white cake mix and mix until combined; dough will be soft but thick. Stir in 1/4 cup of sprinkles - I used red sugar sprinkles which ended up turning my cookie dough a nice shade of pink, but choose whichever kind of sprinkles you like best. Cover bowl with plastic wrap and refrigerate for at least two hours or up to overnight. Preheat and prepare the pans. Preheat the oven to 350 degrees and line two baking sheets with parchment paper. Set aside. Roll and bake. Place the powdered sugar in a shallow bowl and the remaining 1/4 cup of sprinkles in another bowl. Using a 1-inch cookie scoop, scoop out dough and roll into a ball. Sprinkle with a few extra sprinkles and roll in powdered sugar, completely covering the dough ball. Place on a prepared cookie. Repeat with remaining dough. Bake for 10 minutes, rotating the pan halfway through the baking time. Allow cookies to cool on baking sheet for two minutes then transfer to a cooling rack to cool completely. Store at room temperature in an air tight container up to five days. Adapted from The Recipe Critic