I halved the tomatoes (15 large) and put them in a heavy saucepan with tight-fitting lid with a few tablespoons of grapeseed oil (olive or oil of your choice may also be used) and let them simmer on low heat for about an hour. I then strained the resultant pulp through a sieve with a wooden spoon and threw away the leftover cup of seeds and skins in the compost. The result was a rather thin soup with no flavourings.
I then reduced this over medium heat until about 2/3 down. Meanwhile, I sautéed 2 cloves crushed garlic and a 5-inch stick of celery (strings removed) in a tablespoon of butter. Once softened, I added this to the soup, together with two sachets of high quality liquid chicken stock and a good grinding of Himalayan rock salt. A handful of basil leaves pounded with ½ cup of parmesan was then thrown into the mix and allowed to develop a flavour on low heat for 20 minutes. 2 teaspoons of light brown sugar softened the acidity.
Served with plenty of parmesan sprinkled on top, it was a surprisingly delicious and light appetiser! Also a great chilled soup!