Preheat the oven to 170F/325?C/Gas Mark 3.

Arrange the tomatoes, cut side facing up, in a roasting tin, then place the red pepper, onion and garlic cloves around the tomatoes. Drizzle with olive oil and balsamic vinegar and season well with salt and pepper.

Sprinkle the sugar over the top and roast for 1 hour. The tomatoes should have dried out a little and the pepper and onion should be soft.

Peel the roasted garlic, then blend everything with the stock and basil. (Add the stock a little at a time until your preferred consistency is reached).

Either serve immediately (seasoning to taste) or allow to cool and refrigerate.