Arrange the halved tomatoes, quartered onion, and whole garlic cloves on a baking sheet.

Drizzle the vegetables with olive oil and season generously with salt and pepper. Toss everything together to ensure the vegetables are evenly coated.

Place the baking sheet in the oven and roast for 40 minutes, or until the vegetables are caramelized and tender.

Allow the roasted vegetables to cool for about 10 minutes. Then, transfer them, along with all the juices from the baking sheet, into a blender. Add the tomato paste and blend until the mixture is smooth.

While the soup blends, stack the basil leaves, roll them tightly, and slice them into thin strips.

Pour the blended soup into four bowls. Garnish each bowl with a sprinkle of fresh basil strips to add a touch of freshness and flavor.