Add thyme, onion and garlic. Sauté until onion is soft, about 5 minutes.
Add tomato paste and continue stirring for 4 minutes.
Add tomatoes, sugar and water.
Bring mixture to a boil, then simmer for 40 minutes.
Either use an immersion/stick blender* directly in the pot or separate soup into batches and process in a blender. Leave soup slightly chunky and return to pot.
Add basil and simmer for another 10 minutes.
Fill bowls with soup and top with croutons and parmesan cheese.
Notes
* An immersion/stick blender is a great kitchen gadget. It makes puréeing soups much easier since you can leave the soup in the pot and avoid the messy process of transferring the mixture to a blender. They sell for $30 - $40.