Preheat the oven to 350°F. Liberally spray a 12-cup muffin tin with baking spray or use cupcake liners. Set aside.
In a medium-size mixing bowl use a whisk to sift together the flour, sugar, baking powder, baking soda, salt and cinnamon.
Make a well in the center of the bowl and add the bananas, eggs, butter and vanilla. Use a large non stick spatula to mix until fully combined.
Divide the batter evenly between the wells in the muffin tin. (Tip: An ice cream scoop works best)
Bake for 20-22 minutes or until a toothpick inserted into the center comes back clean.
Cool for 15 minutes in the muffin tin then remove to a rack to cool completely.
Store chilled or at room temperature in an air tight container.