01 - Peel the bananas and slice them into 1/2-inch rounds. Arrange in a single layer on a parchment-lined baking sheet and freeze for at least 2 hours until completely solid.
02 - Transfer the frozen banana slices to a food processor or high-powered blender. Blend on high, scraping down the sides as needed, until the mixture reaches a smooth, soft-serve consistency, about 2 to 4 minutes.
03 - For flavored nice cream, add vanilla extract, cocoa powder, nut butter, or cinnamon and blend briefly until evenly combined.
04 - Serve immediately for a soft-serve texture, or transfer to an airtight container and freeze for 1 hour for a firmer scoopable consistency.