Preheat the oven to 350°F (175°C).
Mash the ripe bananas in a large bowl until smooth.
Incorporate the softened butter and granulated sugar, mixing until well combined.
Add the egg and vanilla extract, then mix until combined.
In a separate bowl, whisk together the flour, baking soda, and salt.
Gradually add the dry ingredients to the wet mixture, stirring gently just until combined.
Fold in the rolled oats and chocolate chips carefully.
Pour the batter into a greased or lined baking dish and spread evenly.
Bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean.
Allow the bars to cool in the pan for at least 10 minutes before transferring to a wire rack.