You will need a slow cooker that holds around 4 litres/7 pints for this recipe. To freeze the soup, leave to cool completely then pour into sealable containers. Freeze for up to 4 months.
Cover the slow cooker and turn to high. Cook on high for 3 hours, then mash a little using a potato masher. Serve immediately with fresh chopped parsley if you like a ‘chunky’ soup.