How to Make It
Preheat the oven to 350°. Bring a pot of water to a boil; fill a large bowl with ice water. Make a shallow X in the bottom of each tomato. Plunge the tomatoes into the boiling water for 30 seconds or just until the skins begin to curl. Transfer the tomatoes to the ice water to cool. Drain the tomatoes and pat dry, then peel.
Halve the tomatoes crosswise. Set a strainer over a medium bowl. Scoop the seeds from the tomato halves into the strainer and press to extract the juices. Coarsely chop the tomatoes and add them to the bowl; discard the seeds.
In a large saucepan, heat 3 tablespoons of the olive oil until shimmering. Add the onion, carrot, celery, thyme sprigs and bay leaf and cook over moderate heat, stirring occasionally, until softened, about 8 minutes. Add the tomatoes and their juices along with the stock and sugar, season with salt and pepper and bring to a boil. Simmer over moderately low heat until the tomatoes are completely broken down, about 20 minutes.
Meanwhile, in a medium bowl, toss the bread cubes with the remaining 1/4 cup of olive oil and the tarragon and season lightly with salt and pepper. Spread the bread cubes on a baking sheet and toast for about 10 minutes, stirring once, until golden and crisp.
Using a slotted spoon, transfer the solids from the saucepan to a blender. Discard the thyme sprigs and bay leaf. Add the cream to the blender and puree the soup until smooth. Pour the soup back into the saucepan and stir well. Rewarm over moderately low heat and season with salt and pepper. Serve the soup with the croutons on the side. Alternatively, serve the soup lightly chilled.