Preheat oven to 350°F(180°C). Line one large cookie sheet with parchment paper. Lightly oil the paper with oil spray or coconut oil. Set aside.
Peel off the ripe bananas, very ripe bananas with lots of black spots on the skin are the best as this recipe is sugarless. For precision, weight the peeled banana, you need 10.5 oz or 300g.
Roughly cut the banana in pieces and place them into a food processor with the S blade attachment.
Add fresh runny peanut butter and unsweetened cocoa powder.
Process on medium/high speed until it forms a shiny, smooth sticky chocolate cookie batter. You may have to stop the food processor every 30 seconds, scrape down the sides of the bowl with a spatula and repeat until evenly combine and no more banana pieces shows.
If you want to add chocolate chips, add them now and stir into the batter using a spatula, not the food processor blade to avoid breaking the chips.
Scoop dollops of cookie batter using 2 tablespoons and release each dollop onto the prepared baking sheet, leaving 1 thumb space between each cookies. The cookies won't expand while baking.
You can spread out the cookie or leave them thick, as you prefer. I like to use the back of a spoon to gently spread the batter and shape large cookies.
Repeat until you used all the cookie dough and form 8 cookies.
Bake for 9-11 minutes maximum to keep the cookies soft and fudgy.
Remove from the oven and cool 5 minutes on the cookie sheet.
Slide a spatula under each cookie to transfer them onto a cooling rack.
Cool to room temperature before eating.
Store up to 3 days in a cookie jar in the fridge or freeze in zip bags and thaw at room temperature 3 hours before eating.
Peanut butter swap: you can replace peanut butter by sunflower seed butter or almond butter. Make sure you are using fresh natural seed or nut butter with no added oil or sugar. How to increase the sweetness? If your bananas are not very ripe the cookies can't be sweet enough to your liking. Add 1/4 cup of any sugar (coconut, white or brown) into the batter or sugar-free erythritol or a few vanilla stevia drops to boost the sweetness.