By CJ1020
Begin by thinly slicing one medium sized onion. Depending on your taste, you can substitute fresh diced garlic or mix the onions and garlic together. Set the sliced onion aside and finely chop the parsley. You will need approximately ¾ cup of chopped parsley. Either regular or curly Italian parsley is fine; some prefer to substitute basil.
In a large saucepan, pour ½ cup of oil (extra virgin olive oil works best) and warm over medium heat. Add the onions and sauté until they are a light brown color and soft. Stir frequently and try not to overcook.
Once the onions are soft and brown, add the tomato puree and crushed tomatoes and stir. The mixture may begin to splatter slightly at this point, so add 1 can of water to control the splattering and thin the sauce. You may add more than one can if you prefer thinner sauce.