Preheat oven to 425 degrees. In a large oven safe dutch oven, add quartered tomatoes, smashed garlic, chopped onion, fresh herbs, olive oil and a generous sprinkle of salt and pepper. Roast uncovered in the oven for 1 hour.
Remove pot from oven and allow to cool 10 minutes. Add vegetable stock and coconut milk to dutch oven. Blend soup using an immersion blender until smooth, or transfer to a high speed blender, blend until smooth and add back to dutch oven.
Turn dutch oven on medium-low heat and bring to a simmer. Simmer soup for 10 minutes. Add fresh basil and adjust seasoning as needed with salt and pepper.