Preheat your oven to 350°F (175°C) and grease a standard loaf pan with butter or non-stick spray.

In a large mixing bowl, peel and add the bananas. Crush them until mostly smooth with some small lumps.

Stir in melted butter to the mashed bananas, then add sugar, beaten egg, and vanilla extract, mixing until combined.

In a separate bowl, whisk together flour, baking soda, salt, and cinnamon.

Gradually add the dry mixture to the banana mixture, folding it in gently.

Fold in the toasted nuts if desired.

Pour the batter into the greased loaf pan, smoothing the top.

Bake for 55 to 65 minutes, and check for doneness with a toothpick.

Once baked, cool the bread in the pan for about 10 minutes before transferring to a wire rack to cool completely.

Slice and serve after cooling.