Preheat oven to 350 degrees F.
Cream butter and sugar in the bowl of an electric mixer until fluffy, about 3 minutes. Add eggs and vanilla and beat until combined.
Combine dry ingredients in a bowl. Add half of the dry ingredients, mixing until just combined. Add the milk. Once mixed, add remaining dry ingredients. Fold in assorted sprinkles.
Pour into cupcake tins and fill 2/3 of the way full. Bake for 18-20 minutes. Let cool, then frost.