Preheat your oven to 400°F (200°C).
Chop the tomatoes, onion, and garlic. Spread them out on a baking sheet, drizzle with olive oil, and sprinkle with salt and pepper.
Roast the vegetables for about 25 to 30 minutes, or until they are soft and caramelized.
In a blender, combine the roasted vegetables with the fresh basil and broth. Blend until smooth.
Transfer the mixture back to the pot and heat over medium-low heat for about 5-10 minutes, stirring occasionally.
Serve hot with a drizzle of olive oil and a sprinkle of fresh basil on top.