Preheat oven to 350°F. Spray a 9x5-inch loaf pan with cooking spray and set aside.
Using a handheld mixer or stand mixer fitted with the paddle attachment, mix together the butter, granulated sugar, and brown sugar until well combined (about 1 minute). Add in the eggs and vanilla, making sure to mix well after each ingredient. Add the mashed banana and stir by hand.
In a separate bowl, whisk together the flour, baking powder, baking soda, salt, and cinnamon.
Add the dry ingredients to the wet ingredients and mix until just combined, making sure not to overmix the batter.
In a separate bowl mix together the sugar and cinnamon for the cinnamon sugar swirl and set aside.
For one layer of the cinnamon sugar: pour about half of the banana bread into the loaf pan and sprinkle the cinnamon sugar mixture on top, then pour the remaining batter on top.
For two layers of the cinnamon sugar (like the picture above): pour about one-third of the batter in the loaf pan, sprinkle half of the cinnamon sugar mixture on top, and repeat layers, topping with the last third of the banana bread.
Bake for 55-65 minutes or until a toothpick inserted into the center comes out clean. If the banana bread becomes too dark, tent with aluminum foil for the last 15-20 minutes of baking.
Remove from oven and allow to cool in loaf pan for 10 minutes. Remove the bread from the loaf pan and transfer to a wire rack to finish cooling.