Preheat the oven to 200 degrees Celsius (390 degrees Fahrenheit).

Wash the large tomatoes and cut them into quarters. Place all the tomatoes on a roasting tray.

Roast the tomatoes in the oven for about 45 minutes or until they are tender and caramelized.

While the tomatoes roast, heat a pan over medium heat and add one tablespoon of vegetable oil.

Peel and finely chop the onion. Once the oil is hot, add the chopped onion to the pan and fry until golden brown.

Next, peel and chop the garlic cloves and add them to the pan with the onion. Fry for an additional 30 seconds until fragrant.

After the tomatoes are finished roasting, add them to the pan with the onion and garlic.

Pour in the vegetable stock and stir everything together. Let it cook for about 5 minutes.

Add half of the fresh basil to the pot. Season with salt and black pepper to taste.

Remove the pan from heat and let the soup cool slightly.

Pour the soup into a blender and blend until smooth. For a chunkier texture, blend less.

If desired, sieve the soup to remove seeds for a smoother finish.

Transfer the soup back into the pan and reheat gently.

Serve in bowls, garnished with the remaining fresh basil.