Using a food processor, blend the bananas, pumpkin, maple syrup, and pumpkin spice thoroughly. Transfer to a freezer-safe container and freeze for 24 hours.
This does freeze pretty hard. When removing it from the freezer, let it sit on the counter for a bit before trying to dig into it. If you prefer a stronger flavor, feel free to add more pumpkin spice and/or cinnamon. You can taste the bananas and there is no way around that but you can adjust the flavor before you freeze it.
Optional: You can freeze in martini or champagne glasses.