Peel bananas, slice, and place on parchment paper lined baking sheet.
Place in freezer until frozen (I left mine in the freezer overnight)
Add ¼ of the frozen bananas to a high-powered blender or Ninja
Add the remaining ingredients and blend until crumbly.
Continue to add bananas ¼ at a time and blend until the entire mixture is crumbly.
Once the entire mixture is crumbly continue to blend until it becomes smooth and creamy. This will take a couple of minutes and you can usually watch it blend moving from the bottom of the blender upward. You may need to stop the blender and push the mixture in toward the blades once or twice.
Spoon into cups and serve immediately.
Leftovers can be stored in a freezer-safe glass container. When ready to eat let thaw for a few minutes, place back in the blender, and blend again until smooth and creamy.