Preheat the oven to 400°F. Toss the tomato wedges, ¼ cup of the oil, salt, and pepper together. Spread the tomatoes on a baking sheet and roast for 45 minutes.
Meanwhile, in a Dutch oven (at least 6 quarts), sauté the onion, shallots, and garlic in 2 Tablespoons of olive oil, the butter, and red pepper flakes for about 10 minutes, until the onions become translucent.
Add the canned tomatoes, basil, thyme, and chicken stock. Add the roasted tomatoes when they are done, including any juice released in the roasting.
Bring to a boil and simmer, uncovered, for 45 minutes. Use a blender to purée the soup to the consistency you like.
Reheat to serving temperature.
Bon Appétit!