Preheat your oven to 350°F (175°C). Grease a 9x5 inch loaf pan.
In a large mixing bowl, combine the mashed bananas and melted butter, stirring until well blended.
Stir in the maple syrup until fully incorporated.
Add the beaten egg and vanilla extract, mixing until combined.
In a separate bowl, combine the flour, salt, baking soda, and cinnamon. Gradually mix this into the wet ingredients until just combined.
Pour the batter into the prepared loaf pan, using a spatula to smooth the top.
Bake in the preheated oven for 60-70 minutes, or until a toothpick inserted in the center comes out clean.
Once baked, remove from the oven and let cool in the pan for about 10 minutes before transferring to a wire rack to cool completely.