Place the tomatoes in a saucepan of boiling water, 3 or 4 at a time and leave for 1 minute. Remove from saucepan and the skin should peel of quite easily. At this point you should also deseed the tomatoes if that's your preference. I don't bother. Once peeled and chopped put aside.
Fry the onions and garlic in olive oil until the onions are golden but not crisp. Add all the other ingredients including the tomatoes and stir well adding a little water. Bring to the boil and simmer for 10 to 15 minutes, or until the tomatoes have liquefied.
The sauce can be bottled, frozen or use it straight away. It's great for bolognaise and lasagne. I also add capsicum, kidney beans, cumin and chili for a tasty vegetarian meal with pasta and salad.