Toss the tomatoes with1/8 cup olive oil, salt, and pepper. Place them on a baking sheet & then into the oven to roast for 45 minutes.
In an 8-quart stockpot over medium heat, saute the onions and garlic with 2 Tbsp of olive oil, and red pepper flakes for 10 minutes, until the onions start to brown. Add the canned tomatoes, basil, thyme, and chicken stock.
Add the oven-roasted tomatoes, including the liquid on the baking sheet. Bring to a boil and simmer, uncovered for 40 minutes. Pass through a food mill fitted with the coarsest blade, or pulse in your food processor.