Preheat the oven to 350 degrees F. Line a large baking sheet with parchment paper; set aside.

In a large bowl, combine the mashed bananas, nut butter, maple syrup, egg, and vanilla extract. Mix until smooth and well combined.

Stir in the oat flour, flaxseed meal, cinnamon, baking soda, and kosher salt until just combined. Then fold in the rolled oats, hemp hearts, chia seeds, chocolate chips, and walnuts if using. Allow the dough to rest for 5 minutes to thicken.

Using a large cookie scoop, portion about 3 tablespoons of dough per cookie onto the prepared baking sheet, spacing cookies about 2 inches apart. Top each cookie with a few extra chocolate chips.

Bake for 10 to 14 minutes, until cookies are set but still soft to the touch.

Remove cookies from the oven, sprinkle with flaky sea salt if desired, and let cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely. Enjoy!