Preheat oven to 350F (177C) and line a standard 12-cup muffin tin with paper liners.
In a medium bowl, sift together the all-purpose flour, baking powder, and salt to ensure even distribution.
In a stand mixer bowl equipped with a paddle attachment, cream the butter and sugar on medium-high speed until the mixture reaches a light, pale consistency.
Reduce speed to low and incorporate the egg and vanilla extract, scraping the sides of the bowl as necessary.
Add the dry ingredients in three stages, alternating with the milk, starting and ending with the flour mixture.
Mix until the batter is just homogenous; do not over-mix to avoid gluten development.
Distribute the batter evenly among the 12 cupcake liners, filling each approximately two-thirds full.
Bake for 18 to 22 minutes, or until a thermometer inserted into the center reads 205F (96C).
Remove from oven and allow to cool in the pan for 5 minutes before transferring to a wire rack for complete cooling.