1) Yes, but first peel the banana and cut it up into various pieces. Place them on a plate or baking sheet lined with parchment paper. 2) Put them in the freezer for three hours to harden before transferring to a Ziploc bag or Tupperware container, which you should label soon- otherwise things get confusing! 3) The bananas will stay fresh for about two weeks; don't freeze any longer than that because they'll turn into rock-hard chocolate chunks (that's what happened to the bananas I tried!)...