Place sliced tomatoes on a baking sheet. Cover with most of the olive oil (reserving 2 tablespoons), and the salt and pepper. For a little more flavor, add a sprig or 2 of fresh oregano, thyme or rosemary atop the tomatoes. Place in a 400 degree oven for 30 minutes to roast.
Halfway through the roasting, melt the butter and remaining olive oil in a heavy-bottomed pot over medium-low heat. Add the onion, celery, carrots, and garlic, and cook until the vegetables begin to get soft (15 minutes or so).
When the tomatoes are done, add those to the pot (removing the sprigs of herbs), along with the stock. Simmer on low until the vegetables are all tender (another 15 minutes or so).
Puree the soup with an immersion blender or in an upright blender in batches.
Return the soup to the pot and onto the stove. Heat slowly. Add the chopped basil and heavy cream. Season to taste with salt and pepper, and serve.
*To peel the tomatoes, heat a saucepan full of water and bring to a boil. Place the tomatoes into the boiling water for 1 minute. Remove and let cool. The skins will peel off easily after that.
Recipe from http://www.soulemama.com/soulemama/2010/08/our-carrot-tomato-soup.html, retrieved 10/18/10.