Preheat the oven to 350°F (175°C).

Mash the ripe bananas in a large bowl until smooth. Add melted butter and mix well.

Mix in the sugar, eggs, and vanilla extract until combined.

In a separate bowl, combine flour, baking soda, salt, and cinnamon (if using).

Gradually fold the dry ingredients into the wet mixture until everything is just combined. Be careful not to overmix—this can lead to a denser loaf.

Transfer the batter to the greased loaf pan, smoothing the top to ensure an even layer.

Bake for 50 to 60 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs attached.

Allow the banana bread to cool in the pan for 10 minutes, then carefully move it to a wire rack to cool fully before slicing.