Pre-heat oven at 375 deg F. In a large bowl, mash the bananas. Then add the peanut butter and mix until it's creamy.
Add the oats, dates, and salt and more sweetener if using. For the dates, if they are not soft enough, you can soak them first with hot water for 10 minutes, then drain, before adding into the mixture. Mix everything thoroughly by hand or with a spoon.
Scoop about a tablespoon of the dough, roll into a ball and press on the baking sheet. You can also add cashew nuts on top and press it into the batter.
Bake for 13-15 minutes or until nice and golden brown. Then take it out of the oven, and leave the cookies on the tray for another 10 minutes so they stay in form.
Store in airtight container in the fridge for up to a week. Or freeze them for longer storage.
Notes
Choose an all-natural peanut butter by checking the labels/ingredients list which should only have peanuts in it and no other artificial ingredients. If you have nut allergies, you can sub it with tahini (sesame seed butter), or almond butter.