Place in a freezer bag or container and freeze overnight (or for at least 8 hours).
Remove from the freezer.
Place in a food processor.
Process for around 2 minutes until you have a smooth cream. If your food processor is struggling to break down the frozen banana add a little milk or water, a teaspoonful at a time.
For a soft serve-style ice cream serve immediately.
For a more scoopable ice cream transfer the mixture to a freezer-proof dish and return to the freezer for 2 hours.
Serve with sprinkles on top if desired.
Notes
Nutritional information is approximate and is intended as a guide only.