Preheat your oven to 350°F (175°C) and lightly grease a 9x5-inch loaf pan.
In a large mixing bowl, combine the mashed bananas, applesauce, honey (or maple syrup), egg, and vanilla extract. Mix until well combined.
In a separate bowl, whisk together the baking soda, salt, cinnamon, and whole wheat flour.
Gradually add the dry ingredients to the wet ingredients, stirring until just combined. Be careful not to overmix. If using, fold in the chopped nuts.
Pour the batter into the prepared loaf pan and smooth the top with a spatula.
Bake for 50-60 minutes, or until a toothpick inserted into the center comes out clean.
Allow the banana bread to cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.