Preheat the oven to 200°C.
Cut the tomatoes in half and place the close together in two large baking tray. Season with salt and pepper, then sprinkle with the extra olive oil. Bake for 30-40 minutes until soft.
Meanwhile, finely slice the shallots and garlic cloves. Cut the chilli in half and remove the seeds. Heat the oil in a heavy based pan at a low temperature and soften the shallots , chilli and garlic for about 10 minutes. Turn off the heat, and let cool until the tomatoes are ready. Then strain the oil into a large sauce pan, putting aside the fried onion, chilli and garlic.
Gently heat the oil. Press the tomatoes through a sieve into the warm oil. Make sure that that the tomato flesh is completely extruded - only the skin and the pits should remain in the sieve.
Bring the sauce to the boil. Add the sugar and vinegar, then gently simmer for about 30 minutes at low temperature, until you get a thick, silky sauce.