Roast the Tomatoes and Garlic:

1. Preheat the Oven:
   Preheat your oven to 400°F (200°C).

2. Prepare the Vegetables:
   Spread the quartered tomatoes and unpeeled garlic cloves on a large baking sheet. Drizzle with 1 tablespoon of olive oil and sprinkle with salt and pepper.

3. Roast:
   Roast the tomatoes and garlic in the preheated oven for 25-30 minutes, or until the tomatoes are soft and caramelized, and the garlic is fragrant and golden. Stir halfway through to ensure even roasting.

4. Cool:
   Remove from the oven and let the tomatoes and garlic cool for a few minutes. Once cool enough to handle, carefully peel the skins off the garlic cloves and discard.

Make the Soup:

5. Sauté the Onion:
   While the tomatoes and garlic are roasting, heat the remaining tablespoon of olive oil in a large pot over medium heat. Add the chopped onion and sauté for 5-6 minutes, or until softened and translucent.

6. Add the Roasted Vegetables:
   Once the garlic is peeled, add both the roasted tomatoes and garlic to the pot with the onions. Stir to combine.

7. Season:
   Add the dried oregano, red pepper flakes (if using), and a pinch of salt and pepper. Stir to combine, letting the flavors meld for another 2-3 minutes.

8. Add the Broth:
   Pour in the vegetable broth and bring the mixture to a simmer. Let it cook for about 10-15 minutes to allow the flavors to blend.

9. Blend the Soup:
   Using an immersion blender, blend the soup until smooth and creamy. If you don’t have an immersion blender, you can transfer the soup in batches to a regular blender and blend until smooth. Be cautious when blending hot liquids.

10. Add the Cream:
    Stir in the heavy cream and continue cooking for an additional 5 minutes. Taste and adjust seasoning with salt and pepper, if needed.

11. Serve:
    Ladle the soup into bowls and garnish with fresh basil. Serve warm with a slice of crusty bread or a grilled cheese sandwich for the ultimate comfort meal.