Place the broccoli in a large saucepan together with the celery, onion and stock. Bring to the boil then reduce heat partially cover and simmer for 15-20 minutes until the vegetables are very soft.

Allow to cool slightly then transfer to a blender or food processor and process until very smooth.

return the soup to the rinsed out pan, add the remaining ingredients and reheat very gently, stirring constantly and being careful not to allow the soup to boil. Serve hot.