Preheat the oven to 180°C and line a baking tray with parchment paper.
Mash the bananas with a fork.
Add all the other ingredients and combine until you get a malleable dough (you might need to add more oats, it’s too sticky and mushy). Let the mixture rest until the oven warms up.
Make 8 equal-sized balls from the mixture and flatten these slightly between your palms.
Put the cookies on the prepared baking tray, then bake in the middle of the oven for about 20 minutes until golden brown.
Cool the cookies on a wire rack then serve.
Store them in a jar or cake tin, for up to 3 days.