Preheat your oven to 350°F (175°C) and grease a 9x5-inch loaf pan.
In a large mixing bowl, combine the mashed bananas and melted coconut oil. Mix until well combined.
Stir in the brown sugar, honey, eggs, and vanilla extract until smooth.
Add the baking soda, salt, and ground cinnamon to the mixture, stirring until incorporated.
Gradually add the whole wheat flour, mixing until just combined. If using, fold in the chopped walnuts.
Pour the batter into the prepared loaf pan and smooth the top.
In a small bowl, mix the rolled oats and tablespoon of sugar together, then sprinkle this mixture evenly over the top of the batter.
Bake for 50-60 minutes, or until a toothpick inserted into the center comes out clean.
Allow the bread to cool in the pan for 10 minutes, then transfer it to a wire rack to cool completely.