i've actually never heard of plantain ice cream anywhere but i wanted to make it. i don't especially like bananas but i love plantains. and i've heard good things about freezing bananas to make banana ice cream. well, they're family so i gave it a try. i started with ripe plantains from the store, not green. the green ones would not be nearly as sweet.
when i say ripe plantains, for this it doesn't matter if they have bruises all over. actually i've never found a plantain that bruised all the way through their very thick skins. get a dark yellow one, not a green one for dessert stuff. the riper they are, the more starch has converted to sugar. after you freeze it, it will be even sweeter. you could easily use bananas for this the exact same way.