Break the banana chips into small pieces. Peel the bananas and cut them into slices.
Lay the small banana slices on a freezer proof tray (so that the pieces don't touch each other). Freeze for 2 hours until the banana has frozen.
Put the frozen banana and crème fraîche into a food processor and put the lid on.
With dry hands, use the pulse button to blend the banana and crème fraîche - quick little pulses until it mixes up. Put the banana ice-cream into a bowl. Add the banana chips and mix everything together. Return to freezer until set.