Peel and finely dice the onion. Slice the white part of the leek into fine rings (do not use the green end part),roughly chop the tomatoes, peel the garlic and roughly slice it. Remove the basil leaves from the stalk and carefully slice the basil leaves for the garnish (keep the stalks).
Heat a deep saucepan over a medium heat add the sunflower oil. Once the oil is hot, add the leek and the onion and sweat them until transparent. Then add the tomato puree and cook for another 2 minutes. Finally add the thyme, basil stalks, roughly chopped tomatoes and the garlic and allow to cook for 5 minutes.
Once the tomatoes have broken down. Add the water and the double cream and allow to simmer for 15 minutes until the leeks and onion are completely soft.
Remove the pan from the heat and allow to cool for a couple of minutes. Pour the soup into a blender and blitz until smooth. Return the soup back to the pan and season with salt and pepper.
To serve, ladle the soup into bowls and finish with the finely sliced fresh basil.
«Use some sun dried tomatoes in this recipe to enhance the flavour.»