In a large bowl, or bowl of your stand mixer, cream the butter & sugar. Add in egg and vanilla until blended & mixture is fluffy.
Add in the flour, baking soda & powder, and continue to mix on low until the dough comes together. The dough will be on the dry side, so add just enough buttermilk to give you a soft (not wet!!) mixture.
Chill the dough for 10 minutes in the freezer or 30 minutes in the fridge.
While the dough chills, preheat the oven to 375.
Roll dough into balls, and then roll in a bowl of sprinkles.
Bake for 8-10 minutes or until the sides are golden.