Place bananas in a bowl and mash well with a fork.
Alternatively, puree the bananas in a blender or food processor.
Pour the mash or puree into ice cube trays.
Place ice cube trays in freezer until frozen solid.
Either leave the cubes in the trays for future use, or remove the cubes and store in freezer-safe bags.
For recipes, thaw out the desired amount of cubes prior to making the recipe.
For smoothies, remove the desired amount of cubes from the tray and drop into blender before blending.