Heat the oil in a large pan, add the onion and bacon and sweat for 2 minutes. Chop the carrot, celery and leek, add to the pan and cook without colouring for 5 minutes on a medium heat, stirring constantly. Add the basil, tomato puree, tomatoes, stock, potatoes and sugar. Simmer until the potatoes are soft. Push the mixture through a sieve into another pan. The residue in the sieve can be used as a base for stews or lasagne. If you dont want to make your soup spicy, season the soup and top with cream then serve. For a spicy soup, heat some olive oil in a large pan and cook the garlic, peppers and chillies without colouring. Add the base tomato soup and seasoning to taste (Worcester sauce, Tabasco etc). Add the sausage and coriander, simmer for 5 minutes and serve. To make the chilli salsa, pound the dry ingredients in a pestle and mortar or blend in a food processor. Slowly add the oil, and use as a dip for bread.