Preheat your oven to 350°F (175°C) and grease your loaf pan with a bit of coconut oil or line it with parchment paper for easy removal.
In a large mixing bowl, whisk together the whole wheat flour, baking soda, baking powder, salt, and ground cinnamon until well combined.
In another bowl, combine the melted coconut oil, coconut sugar, and unsweetened applesauce. Mix well until smooth. Add in the lightly beaten eggs and vanilla extract, stirring until everything is nicely combined.
In a separate bowl, mash the very ripe bananas until you have about 1 and 1/4 cups of mashed banana.
Add the mashed bananas to the wet mixture and stir until combined. Slowly fold the wet ingredients into the dry ingredients using a spatula, being careful not to overmix.
Gently fold in the fresh blueberries, ensuring they are evenly distributed throughout the batter. Optionally, place the sliced banana on top for a decorative touch.
Pour the batter into your prepared loaf pan and smooth the top. Bake for 50-60 minutes or until a toothpick inserted in the center comes out clean.
Once baked, remove the banana bread from the oven and let it cool in the pan for about 10 minutes. Then, transfer it to a wire rack to cool completely.