Snickerdoodle Banana Bread

Preheat the oven to 350 degrees F. Grease a 9 X 5 loaf pan.
In a large bowl, combine the mashed bananas with melted butter. Stir in the vanilla extract, and eggs until smooth.
Add the granulated sugar, brown sugar, baking soda, salt, cream of tartar, and cinnamon. Stir until well combined.
Gently fold in the flour until just incorporated. Avoid over-mixing.
In a small bowl, mix together the sugar and cinnamon for the topping.
Pour half of the banana bread batter into the prepared loaf pan. sprinkle half of the cinnamon-sugar mixture over it. Add the remaining batter on top and sprinkle the rest of the cinnamon-sugar mixture.
Bake in the preheated over for 55-65 minutes, or until a toothpick inserted into the center of the bread comes out clean.
Allow the bread to cool in the pan for about 10 minutes, then transfer it to a wire rack to cool completed.