Preheat the oven to 350°F (175°C) and line a muffin tin with cupcake liners.
In a bowl, whisk together flour, baking powder, and salt.
In a separate bowl, beat butter and sugar until light and fluffy.
Add eggs one at a time, then mix in vanilla extract.
Alternately add dry ingredients and milk with sour cream, mixing until just combined.
Divide the batter into cupcake liners, filling each about 2/3 full.
Bake for 18-20 minutes or until a toothpick inserted comes out clean.
Let cool completely before frosting with vanilla buttercream.