Preheat the oven to 350°F. Line cupcake tins with wrappers.
In a medium bowl, sift together the flour, baking powder and salt.
In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and sugar until light and fluffy, about 2 minutes. Add the eggs one at a time then add the scraped vanilla bean seeds and vanilla extract and beat until combined.
Alternately add the flour mixture and milk, beginning and ending with the dry ingredients, and beat just until the batter is combined.
Fill each cupcake cup 2/3 full with batter then bake the cupcakes for 15 to 18 minutes until a toothpick inserted comes out clean. Remove the cupcakes from the oven and transfer them to a rack to cool completely while you make the frosting.