Preheat the oven to 350°F. Grease a 9×5-inch loaf pan with a non-stick spray or line it with parchment paper, allowing some overhang for easy removal.
In a medium-sized bowl, whisk together the whole wheat flour, baking soda, sea salt, and cinnamon.
In a larger bowl, mix the mashed bananas with the unsweetened applesauce, brown sugar, eggs, and vanilla extract.
Gradually fold the dry ingredients into the wet mixture.