Preheat oven to 350 degrees F. Grease a 9x5-inch loaf pan with nonstick cooking spray and set aside.
In a medium bowl, whisk together 1 3/4 cups flour, baking powder, baking soda, salt, and cinnamon. Set aside.
In a large bowl, combine the mashed bananas with the sugar and mix until smooth. Stir in the eggs until well combined. Pour in the melted butter, buttermilk, and vanilla extract and mix until combined.
Add the dry ingredients and mix until just combined, don’t over mix.
In a small bowl, toss the blueberries in the remaining tablespoon of flour. Gently fold the blueberries into the batter.
Pour the batter into the prepared loaf pan and sprinkle turbinado sugar over the top. Bake until golden brown and a toothpick or cake tester comes out clean, about 55 to 65 minutes. If the top is browning too quickly, you can cover the pan loosely with aluminum foil.
Remove the bread from the oven and let sit in pan for 10 minutes. Loosen with a bread knife around the edges and carefully remove the bread from the pan. Cool completely on a cooling rack before slicing.