Place all the ingredients in a blender, season with sea salt and lots of ground black pepper and blitz until smooth.
Transfer to a non-stick saucepan, stir in enough water to reach your preferred consistency and heat through gently.
Season to taste and pour into bowls or mugs to serve with basil leaves to garnish, if you like.
Tip: Serve with a slice of wholegrain or seeded sourdough bread. Add a tablespoon of cooked diced bacon or chorizo to the soup for added flavour and protein, and a liberal drizzle of olive oil.
