Preheat oven to 400 degrees F.
Place cut tomatoes on a baking sheet.
Drizzle with olive oil, sprinkle with salt and fresh ground pepper.
Roast for 45 minutes.
In 8 quart pot, add about 2 Tbsp olive oil and sauté onions, garlic and red pepper flakes over medium heat.
Stir until onions begin to caramelize.
Add the canned tomatoes, basil.
Thyme and vegetable stock.
Then add the oven-roasted tomatoes, including any liquid on the baking sheet.
Bring to a boil and simmer uncovered for about 40 minutes.
Turn stove off and let cool for about 15 minutes.
Use immersion blender to puree soup to desired consistency.
Add additional salt and pepper as needed.