Preheat your oven to 350°F (175°C) and line baking sheets with parchment paper.
In a bowl, mash the ripe bananas with a fork until smooth.
In another bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy.
Beat in the egg and vanilla extract until well combined.
In a separate bowl, whisk together the rolled oats, all-purpose flour, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Fold in the chocolate chips until evenly distributed throughout the cookie dough.
Using a cookie scoop or spoon, drop rounded portions of dough onto the prepared baking sheets, leaving space between each cookie.
Bake in the preheated oven for 10-12 minutes or until the edges are golden brown.
Allow the cookies to cool on the baking sheets for a few minutes before transferring them to a wire rack to cool completely.