Basil and Tomato Sauce

3 T olive oil
2 medium size onions, thinly sliced
1 clove garlic, finely minced
3 stalks celery, chopped
1 carrot, scraped and slices
16 or more fresh basil leaves or 1 t dried basil
1 (1lb 3 oz) can of tomatoes, preferable the Italian kind
3/4 c tomato puree
1 c water
salt to tast
2 bay leaves
1/2 t oregano

Heat the olive oil in a saucepan and cook the onions and garlic until the onions are wilted and transparent. Add the remaining ingredients and simmer, partially covered, three to four hours. Put the mixture through a sieve or a food mill and cook one or two hours longer. This sauce is best when it is cooked for a total of five hours. Yield: two to three cups of sauce.