Preheat oven to 375°F. Line baking sheet with parchment paper.
In a small bowl, whisk together flour, baking powder and salt.
In the bowl of a stand-mixer with paddle attachment, or in a large bowl with hand mixer, beat together butter, cream cheese and sugar until well combined. About 2 minutes. Scrape down sides of bowl as needed.
Add egg and vanilla extract on low. Add flour mixture all at once. When flour is nearly incorporated, add ½ of the sprinkles (48g, ¼ cup).
Divide dough into 8 equal portions, dough will be slightly sticky. Shape each portion into a ball, dip the top half of the dough into the remain sprinkles, place evenly on prepared baking sheet.
Flatten top of dough balls with palm of your hand.
Bake 12-14 minutes, until the bottoms just begin to brown and the top is still slightly soft.
Cool completely on cooling rack.
