Sauté the onion and celery in a medium sized pot until soft [about 5 minutes].
Add all the rest of the ingredients [except the cream] and allow to simmer for 45 minutes.
Use an immersion blender, and blend until smooth.
Now, stir in the cream.
Garnish with fresh basil and serve immediately.
Tips and Tricks:
1. We like to put about 12 x 1 tbsp of shredded parmesan on baking paper and into the oven at 400F/200C for 5-10 minutes until golden as crisp. These little cheese rounds are great for dipping into the soup.