Starting half a day ahead, put the flesh of one avocado in a food processor or blender. Add the
spring onions, garlic and lemon juice and puree until smooth. Add the second avocado and puree,
then the third, with the spices and seasoning. Puree until smooth.
Gradually add the chicken stock. Pour the soup into a metal bowl and chill.
To serve, stir in the iced water, then season to taste with plenty of salt and black pepper.
Garnish with chopped parsley and serve immediately.