Roast Tomato and Thyme Soup

I make this soup with the cheapest of salad tomatoes from the supermarket or greengrocer, partly because the recipe calls for such a great quantity of them, and partly because I love the transformation from slightly hard, insipid, unloved tastelessness to deep scarlet and flavour-drenched, simply by popping them in the oven. I deliberately leave this soup very simple, unadorned to really appreciate the buttery smooth, rich taste of the tomatoes, scattered with a little thyme and black peppe