Wash your hands with soap and water, then gather all your kitchen gear and ingredients and put them on a clean counter.
Peel the bananas and slice them thickly.
Lay them on a plate and freeze until solid, around 2 hours.
Put them in the blender or food processor and turn the machine on to blend them. At first they will want to spin around and stay icy, but keep at it, stopping the machine and using the wooden spoon to loosen the mixture if it stops moving. At some point, it will suddenly go creamy and custardy, like soft-serve ice cream—but if it doesn’t, add a little milk and blend until it does.
Serve right away.
To vary the flavor of your ice cream, try adding any of the following: