Peel and chop the bananas up into bite-sized pieces.
Freeze the banana pieces in a single layer for 1-2 hours (or up to overnight, just let them defrost in the fridge or on the counter to be soft enough to pulverize in the food processor).
Place banana pieces in a bowl of a food processor or blender and pulse until the texture is smooth and creamy, scraping down the sides if necessary. If using, pulse or mix by hand desired add-ins.
Serve using an ice cream scoop. If using, top with add-ins. Store remaining ice cream in an airtight container in the freezer.