Preheat your oven to 350º F. Line a cupcake pan with liners.
Sift together the flour, baking powder, and salt into a large bowl.
In a separate bowl, mix the milk and vinegar and let it sit for a minute.
Using a mixer, beat the butter until creamy, then add sugar and vanilla, beating until light and fluffy.
Alternate between adding the dry ingredients and milk mixture to the butter mixture, starting and ending with dry ingredients.
Divide the batter among the cupcake liners, filling each about three-quarters full..
Bake for 18-22 minutes or until a toothpick comes out clean. Let them cool before frosting.