Let your bananas fully ripen until the brown spots appear all over.
Once your bananas ripen, peel them and put them in a large zip-lock bag. Seal the bag tight with as little air as possible. Stick it in the freezer and freeze it overnight
When your bananas are frozen all the way, put some frozen bananas in the blender, and blend until it becomes a smooth creamy texture, like a soft serve. If you have a Vitamix, use the handy dandy tamper to jam the bananas into the blade to help it blend. If you don't have a high speed blender like Vitamix or Blendtec, you can use the food processor instead. But you should cut up the bananas into smaller pieces before you freeze them, to make it easier for the food processor.
Banana bunches ripen all at once, so for some people it can be difficult to eat them all before they go bad. If you want to slow down the ripening process, just separate the bananas. I personally like to dedicate a couple of banana bunches just for freezing, and freeze them all at the same time. That way, you can have it ready anytime for smoothies and banana ice creams.
Recipe by Mariko Sakata | Raw Food and Plant-based Recipes at https://marikosakata.com/1-ingredient-raw-vegan-banana-ice-cream/