Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a large mixing bowl, combine the mashed bananas, granulated sugar, melted butter, vanilla extract, and egg. Stir until well combined.
Sprinkle the baking soda, salt, and ground cinnamon over the mixture, then gently mix in.
Gradually add the all-purpose flour, stirring until just combined. Be careful not to overmix.
Fold in the chocolate chips if using.
Using a spoon or cookie scoop, drop rounded tablespoons of dough onto the prepared baking sheet, leaving space between each cookie.
Bake for 10-12 minutes, or until the edges are lightly golden.
Remove from oven and let the cookies cool on the baking sheet for 5 minutes before transferring them to a cooling rack to cool completely.