Preheat oven to 350°F and line a muffin tin with cupcake liners
Whisk together flour, baking powder, baking soda, salt and cinnamon in a separate bowl. Set aside.
In a large mixing bowl, cream together butter and sugar until light and fluffy.
Add in eggs, bananas and vanilla with butter and sugar. Mix until well-combined.
Slowly add in your dry ingredients, alternating with the buttermilk. Mix until everything is just combined. Try not to overmix.
Place about 1/4 cup of batter in each cup of your lined muffin tin (Or until they're about 3/4 of the way full). Bake at 350° for 18-20 minutes, or until a toothpick inserted comes out clean.
Allow to cool completely before frosting.