Place all of the ingredients except the reserved potato and scallions into a blender and blend until smooth and creamy. Add a bit of extra water, broth or plant based milk if you would like the soup a bit thinner.
Place mixture into a soup bowl and top with the chopped potato and sliced scallions. As an optional extra you can also sprinkle over some paprika.
For full video tutorial, see the video at the top of this recipe page.