When bananas become very ripe, speckled with brown spots, peel them, wrap them in plastic wrap, and put them in the freezer. Let them freeze at least overnight. You will need a food processor for this recipe, a blender won't work.
Unwrap frozen bananas. Don't use more than 3 per batch. Cut bananas into chunks about 1 inch long. Put into the bowl of the processor fitted with metal blade. Turn on machine. Then bananas will bounce around. Add a few tablespoons of milk or cream and occasionally scrape down the sides of the bowl. After a minute or two of processing the bananas will turn into a beautiful creamy ice cream. My kids love this!