Preheat oven to 375 degrees Fahrenheit
Combine all wet ingredients - buttermilk, egg, vanilla, and mashed ripe bananas.
In a separate bowl combine all dry ingredients - flour, sugars, salt, baking powder, baking soda, and cinnamon.
Fold wet ingredients into dry ingredients.
Fill mini muffin tin with batter, 3/4 way full.
Bake 12-16 minutes