Using an immersion blender, blend all the ingredients together, stopping and stirring frequently with a spatula so that everything is blended together. Alternatively, use a food processor to process all the ingredients together. Transfer the ice cream to a container and freeze for at least 4 hours.
Preheat oven to 200C / 400F. Sprinkle caster sugar on a baking sheet, lay the puff pastry on top and sprinkle with more caster sugar. Bake for 15 to 20 minutes until puffed and crispy. Let cool before serving with ice cream.