Tomato soup

Name: Tomato soup
Ingredients: 2 onions, peeled and chopped; 1 carrot, peeled and diced finely; 1 clove garlic, peeled and crushed; 1 stick celery, finely chopped; 2 tbsp olive oil; 450g/1lb fresh ripe tomatoes, halved; 1 litre/1¾ pints vegetable stock; 1 tsp sugar; Salt and freshly ground black pepper; Handful fresh basil, shredded (optional)