Preheat your oven to 400°F (200°C) while you prepare the ingredients.
Cut the tomatoes in half and arrange them on a baking sheet. Drizzle with 1 tablespoon of olive oil and season with salt and pepper. Add peeled garlic cloves.
Place the baking sheet in the oven and roast for 25-30 minutes, or until the tomatoes are caramelized and slightly shriveled.
In a large pot, heat the remaining tablespoon of olive oil over medium heat. Add the chopped onion and cook until translucent, about 5 minutes.
Once the tomatoes are ready, scoop them into the pot along with the roasted garlic. Add the fresh basil (reserve a few leaves for garnishing) and vegetable broth.
Let the mixture simmer for about 10 minutes to allow the flavors to meld together.
Use an immersion blender to puree the soup to your desired consistency.
Add more salt and pepper if needed. If you prefer a creamier texture, stir in a splash of cream or coconut milk.
Ladle the soup into bowls, garnish with fresh basil leaves, and enjoy!