To make the cranberry sauce, add all ingredients (except the frozen bananas) into a medium sized saucepan, and heat on a low heat until the cranberries are soft and have burst, leaving you with a thick, sticky sauce. Set aside.

Add the frozen bananas into a food processor and blend until you have a smooth ice cream consistency. This can take a while and keep scraping down the sides of the processor to incorporate all the bananas.

In a loaf tin, add one third of the banana mixture and spread so it covers the bottom. Add some blobs of cranberry sauce and swirl it into the banana mixture to create a marbled effect. Then repeat until you've used all the banana mixture. You will probably have some cranberry sauce leftover, so store this in an airtight container in the fridge.

Cover the loaf tin with cling film and put in the freezer for 2 hours. Let sit out for 5-10 minutes before scooping and serving.