01 - Preheat oven to 350°F (175°C). Line a 12-cup muffin tin with paper cupcake liners.
02 - In a medium mixing bowl, whisk together the flour, baking powder, and salt until evenly blended. Set aside.
03 - Using an electric mixer in a large bowl, beat the softened butter and granulated sugar together until pale and fluffy, approximately 2–3 minutes.
04 - Add eggs one at a time, beating thoroughly after each addition. Mix in pure vanilla extract until incorporated.
05 - Add half of the dry mixture to the butter mixture and mix just until combined. Pour in the milk and mix briefly, then add the remaining dry mixture. Mix until no streaks remain—do not overmix.
06 - Portion the batter evenly into the lined muffin tin, filling each cup about 2/3 full.
07 - Bake in the center of the oven for 16–18 minutes, or until a toothpick inserted in the center comes out clean.
08 - Remove tin from oven and let cupcakes cool for 5 minutes before transferring to a wire rack to cool completely.
09 - In a bowl, beat the softened butter until creamy. Gradually add powdered sugar, then mix in vanilla extract, milk or heavy cream, and a pinch of salt. Continue to beat until light and fluffy.
10 - Using a spatula or piping bag, frost the cooled cupcakes as desired.