Soupe de Tomate from The Cooking of Provence by Patricia Lousada

Ingredients

• 2 tablespoons olive oil
• 2 shallots, chopped finely
• 1 kg (2 lb) good-flavoured tomatoes, quartered
• 1 celery stick, chopped finely
• 600 ml (1 pint) chicken stock
• a pinch of sugar
• salt and pepper
• 2 tablespoons chopped basil