Combine the tomatoes, onion and garlic in a mixing bowl and season with olive oil, salt and pepper. Lay out on a baking tray and sprinkle with the thyme, basil and sugar. Roast in the oven at 425 degrees until caramelized.
Pour the tomatoes into a blender and puree. While the blender is running, ladle in hot stock to smooth the soup. You may not use all of the stock. Chicken Stock may be subsitituted for vegetable stock.
For garnish, heat 2 tbsp olive oil, lightly sauté 4 small clusters of cherry tomatos on the vine. Serve on top of the soup with 4 basil leaves, thinly sliced.