Preheat the oven to 350˚F (177˚C) and coat an 8x8 inch baking pan with non-stick cooking spray.

Mix Wet Ingredients: In a large mixing bowl, mash the banana into a smooth paste using a fork, potato masher or immersion blender. Add the peanut butter, maple syrup, and vanilla extract. Mix until well combined.

Add Dry Ingredients: Mix in the old-fashioned oats, oat flour, baking soda, cinnamon, and salt and mix to combine into a thick dough. Stir in the chocolate chips.

Bake Bars: Transfer dough to the prepared 8x8 inch pan and use a spatula, wooden spoon or your fingers to press it an even layer. You don't want them completely smooth on top, just be sure to spread the mixture evenly in the pan. Sprinkle a few extra chocolate chips on top if desired. Bake at 350˚F (177˚F) for 17-18 minutes or until a toothpick comes out clean.

Cool, then Slice: Let cool for at least 30 minutes before slicing and serving. This helps ensure the bars stay together. I recommend letting them cool completely.