1. Put all the frozen bananas, almond milk and the crunchy peanut butter into a blender and whizz together until smooth. This will take a while, keep scraping down the sides and separate any banana chunks that have become frozen together.
2. Once smooth, remove the blender blade and stir in the chopped chocolate. Tip the ice cream into a freezer container dotting and swirling in the remaining peanut butter as you go, cover and freeze until set. Remove from the freezer 10 minutes before serving.