Preheat your oven to 350°F. Lightly grease a standard 9×5-inch loaf pan with a non-stick spray or a bit of coconut oil. You can also line the bottom with a piece of parchment paper.
Peel your bananas and in a large mixing bowl, mash them until smooth. Crack in the egg, pour in the vanilla extract, and add both the brown and coconut sugars. Sprinkle in the cinnamon for that warm, spicy aroma. Stir everything together..
In a separate bowl, whisk together the whole wheat pastry flour, baking powder, baking soda, and sea salt.
Add the dry ingredients to the banana mixture in batches, stirring gently after each addition just until the flour disappears. Overmixing is a no-no—it can make your bread tough. Now, fold in the unsweetened applesauce until just combined.