What can be used to substitute mashed banana in bread?

I am about to find out!

Personally I've done it a few times. I've never tried it with a green plantain as they are starchy and more like a potato, but I've had great results with ripe plantains. My recipe calls for 3 medium cavendish bananas, but I usually use 1 decent sized plantain and 1 regular cavendish banana. You may want to lessen the sugar you add slightly though, as the plantains seem to be sweeter than a typical banana when ripe (of course this might just be my taste). Good luck