Preheat oven to 350°F and line a large, rimmed baking sheet with a piece of parchment paper or a Silpat® baking mat.
In a high-speed blender or a food processor, blend one cup of rolled oats into flour and set aside.
In a large mixing bowl, mash the banana with a fork until smooth. (A few chunks are okay). Add the oat flour, remaining rolled oats, baking soda, cinnamon, maple syrup, and salt. Stir vigorously to combine, and then fold in the raisins.
Scoop out 2 tablespoons per cookie from the mixture and form into balls. Place each cookie onto the prepared baking sheet without overcrowding.
Place in the pre-heated oven and bake until the cookies are lightly golden brown and just barely set to the touch, approximately 16-20 minutes. Remove from oven and cool for at least 15 minutes before serving. Enjoy!