Whisk together the flour, baking powder, and salt. Set aside.

Using an electric mixer on medium speed, cream together the sugar and butter until crumbly. Add the eggs and vanilla, and mix until completely incorporated and smooth.

Add half of the flour mixture and half of the milk to the bowl, and stir until just combined. 

Add the remaining flour mixture and milk, stirring to combine and scraping down the sides as needed. Gently fold in the sprinkles. Do not over-mix; only mix just until combined.

Divide the batter evenly among the prepared muffin cups, filling each about two-thirds full. 

Bake the cupcakes for 25 to 30 minutes, or until a toothpick inserted into the center comes out clean. The centers of the cupcakes should be set and the edges just beginning to brown.

Cool the cupcakes in the pans for about 10 minutes, and then remove them from the pans and place them on a wire rack to cool completely before frosting.

Using an electric mixer on medium speed, beat the butter until light in color, about 3 minutes. Add the confectioners’ sugar and mix until combined. The mixture will be crumbly and dry. 

Add the vanilla and milk, and mix until smooth. Transfer to a piping bag for easy decorating. 

Once the cupcakes are cool, frost each cupcake with 2 to 3 tablespoons of frosting and garnish with sprinkles.