First, preheat oven to 350F and line 2 cookie sheets with parchment paper.
Then, in a large bowl, mash 3 bananas. You'll want your bananas to be very thin and runny. Next, add in vanilla, peanut butter, and coconut oil.
Add in quick cooking oatmeal, peanut flour, ground flax seed, and baking powder, and mix until combined. At this point, I suggest tasting the batter. Don't worry, there's no eggs, this batter is completely edible! If you'd like, add in 1/4 cup of your choice of sweetener, do it now. I opted not to do this because I personally don't like super sweet cookies. You can also add chocolate chips, too :D
Next, spoon 2 tablespoons of batter into your palm. Roll into a ball and place on cookie sheet. Then press into a cookie shape. These cookies wont rise or expand much. Repeat.
Bake at 350 for about 20 minutes or until they begin to brown.