Preheat oven to 350°. Line a loaf pan with parchment paper and set aside.
In a large mixing bowl, whisk together the mashed bananas, coconut oil, maple syrup, egg, applesauce, and vanilla until well blended.
Add in the baking soda, salt, flour and walnuts, and mix until everything is just moistened—do not overmix.
Transfer the batter to the prepared loaf pan. Bake in preheated oven for 45-55 minutes, or until the top is golden brown, and a toothpick inserted into the center comes out clean. Let cool completely before slicing.