Preheat oven to 350 degrees, line muffin pans with cupcake liners (this recipe makes about 30 cupcakes)
In a medium bowl, whisk the flour, baking powder, baking soda and salt for 30 seconds, set aside.
In another bowl, add the buttermilk, vanilla and mashed bananas. Blend and set aside.
In the bowl of your mixer, add the slightly softened butter and mix at medium speed until smooth.
Gradually add the sugar and continue to mix on medium speed for 3 to 5 minutes until lightened in color and fluffy.
Add the eggs one at a time mixing until the yellow of the yolk disappears.
With the mixer on low speed, alternately add the flour mixture and buttermilk mixture, beginning and ending with the dry ingredients (3 additions of dry ingredients and 2 of liquid. Mix just until well blended- be careful not to over-mix.
Add the banana cake batter to the cupcake liners. We put about ¼ cup batter into each liner.
Bake at 350℉ for 15-18 minutes. (Ours were done closer to 18 minutes.)