Preheat oven to 350F.
Place 20 muffin wrappers (if using the stiff kind pictured above) on a baking sheet, or line 20 muffin cups with paper liners.
In a large mixing bowl, cream together butter and sugar. When light and fluffy, beat in the eggs one at a time.
In a medium mixing bowl, whisk together flour, baking powder and salt. In a measuring cup, combine the buttermilk and vanilla extract.
With the mixer on low speed (or by hand), stir one third of the flour mixture into the butter mixture. Blend in half of the buttermilk, followed by another third of the flour mixture. Stir in remaining buttermilk/vanilla and the rest of the flour, mixing only until no streaks of flour remain. Divide evenly into prepared muffin cups, filling each about 2/3 full.
Bake for 22-24 minutes, until a tester inserted into the center comes out clean and the top springs back when lightly pressed. Cool in pan for 2-3 minutes, then transfer to a wire rack to cool completely before frosting.

I used my standard buttercream recipe for this cupcake.

2 sticks butter, 4 cups powdered sugar, 1 tsp vanilla, pinch salt and 2 tbls milk or cream.