- Preheat the oven to 350°F. Line a 9-inch loaf pan with parchment paper then grease the parchment paper with cooking spray. 
- In a large bowl, whisk together 2 cups of flour with the sugar, baking soda, cinnamon and salt. Set the bowl aside. 
- In a separate medium bowl, whisk together the mashed bananas, buttermilk, eggs, melted butter and vanilla extract. 
- Add the wet ingredients to the dry ingredients and stir just until combined. 
- In a small bowl, combine the diced apples with 1 Tablespoon flour, tossing until they’re thoroughly coated. Fold in the diced apples then pour the batter into the prepared loaf pan. Sprinkle the top liberally with sanding sugar (optional).  
- Bake the bread for about 55 minutes, or until a toothpick inserted comes out clean. Remove the bread from the oven and allow it to cool in the pan for 10 minutes before transferring the loaf to a cooling rack to cool completely.