Put all the ingredients for the soup into a blender, in batches if necessary, and make sure everything gets blitzed.
Taste for seasoning: this soup needs careful tasting and adjusting. You may need a drop more lemon juice, white balsamic or extra-virgin oil, rather than salt or pepper.
Chill well, then serve in bowls with chopped walnuts, cucumber matchsticks, dill and rose petals.
