Preheat your oven to 400°F.
On a large baking sheet, arrange the halved tomatoes, onion, garlic cloves, and red bell pepper. Drizzle with olive oil, and sprinkle with dried basil, thyme, salt, and pepper. Toss to coat the veggies evenly.
Roast the vegetables for 25-30 minutes, or until the tomatoes and peppers are soft and slightly caramelized (turning brown). The garlic and onions should also be soft and golden.
Once roasted, transfer the vegetables to a blender or food processor. Add about 1 cup of vegetable broth and blend until smooth. You can also use an immersion blender directly in a pot.
If you prefer a chunkier texture, blend less; for a smoother soup, blend thoroughly.
Pour the blended mixture into a large pot. Add the remaining vegetable broth, and bring the soup to a simmer over medium heat. Let it cook for about 10 minutes, allowing the flavors to come together.