Preheat the oven to 350 degrees F (175 degrees C). Lightly grease a 9x5 inch loaf pan with cooking spray.
Combine butter, coconut sugar, and brown sugar in a large bowl; beat with an electric mixer until smooth and creamy, 2 to 3 minutes. Stir in mashed bananas and applesauce until well blended.
Combine flour, baking soda, baking powder, and salt in a separate bowl. Add banana mixture, stirring just enough to moisten. Fold in walnuts. Pour batter into the prepared loaf pan.
Bake in the preheated oven until a toothpick inserted into center of the loaf comes out clean, 60 to 65 minutes. Let bread cool in the pan for 10 minutes, then turn out onto a wire rack.
Vegan Banana Bread · Dinner Match Lab | Dinner Match Lab