You might also want to put a plastic bag over your bananas if you are deliberately leaving them to ripe more. Two of my bananas turned out to be overrun by maggots and I was absolutely shocked and disgusted. I even needed to take a breather of 5 minutes to recover from that shock and to muster the courage to peel even more bananas!
Due to the addition of yogurt, while still retaining some of the moisture of normal cakes by adding some butter and cake, these mini cakes are extremely moist, so moist they might even stick to each other! Especially useful recipe if you have spare yogurt on hand!
I also added chocolate chips because I really love the combination of chocolate and banana. You can definitely omit it, and you can definitely substitute it for nuts of the same amount too!