I hate waste and decided to try an experiment with the kids. But I wouldn't tell them exactly what they were eating. Not that I would lie to them, but if I introduced the item as, "old bananas you wouldn't eat," I might as well just throw the whole thing in the garbage.
So I mashed one of the bananas until it was creamy in consistency, dipped a fork into peanut butter, and pulled out as much as would stick to the fork, creamed it into the mashed banana, and spread it onto crackers.
The kids LOVED it. I tried it on toast, and they ate that too. Next I will try it on bagels and English muffins.
WARNING! Never let the kids watch you make this spread. If they see you using OLD bananas they probably won't eat it, and if you call it peanut butter with banana, the probably won't try it, either, but if you call it "Banana Nut Spread," they will be curious. They might even like it as much as the kids in my daycare did. (Obviously not for children with peanut allergies.)