Preheat the oven to 400°F (200°C). Line a baking sheet with parchment paper.

Prepare the vegetables: Place halved tomatoes, onion, and garlic cloves on the baking sheet. Drizzle with olive oil, sprinkle with salt and pepper, and toss to coat evenly.

Roast the vegetables: Roast for 25–30 minutes, or until the tomatoes are caramelized and tender.

Blend the soup: Transfer the roasted vegetables to a large pot. Add the vegetable broth and fresh basil leaves. Use an immersion blender (or a regular blender in batches) to puree until smooth.

Simmer and season: Bring the soup to a gentle simmer over medium heat for 10 minutes. Add sugar if desired, and adjust salt and pepper to taste.

Make it creamy (optional): Stir in heavy cream or coconut cream for a rich, velvety texture.

Serve and enjoy: Ladle into bowls and serve warm with crusty bread or alongside a classic grilled cheese sandwich for the ultimate comfort soup pairing.