Lay out approximately 12 cupcake cases or silicone muffin cups on a small baking sheet or tray (this will need to fit in your freezer, so it may be worth checking it for size before you start).
Peel the banana and pop it onto a plate. Mash up with a fork until most of the lumps have gone. Young children might find this step easier to do with a potato masher if you have one.
Tip the mashed banana into a bowl and dollop in the yogurt. Whisk together until well combined.
Using a spoon, dollop some yogurt and banana mixture into the bottom of each cake case until all the yogurt has gone. Top with the banana chips if wanted. We topped half of ours with whole ones and half with broken pieces, I think both ways looked great!
Place the cups (still on the baking tray) into the freezer and leave to freeze for a couple of hours until set solid.
Once frozen through, remove from the cases and serve (or bag up and pop straight back in the freezer to eat later).