http://www.bonappetit.com/recipe/creamy-tomato-soup
Melt butter in a large heavy pot over medium heat. Add thyme, onion, and garlic. Cook until onion is completely soft and translucent, 10–12 minutes. Increase heat to medium-high; add tomato paste. Continue cooking, stirring often, until paste has begun to caramelize in spots, 5–6 minutes.
Add tomatoes with juices, 1 tsp. sugar, and 8 cups water to pot. Increase heat to high; bring to a simmer. Reduce heat to medium. Simmer until flavors meld and soup reduces to about 2 quarts (8 cups), 45–55 minutes. Remove soup from heat; let cool slightly. Discard thyme sprigs. Working in small batches, purée soup in a blender until smooth. Return to pot.
Stir in ¼ cup cream. Simmer soup until flavors meld, 10–15 minutes longer. Season to taste with salt, pepper, and remaining 1 tsp. sugar. Add more cream, if desired.