There are as many recipes for "real" tomato sauce as there are people who cook tomato sauce. Here is D's humble opinion on how to make a cheap, easy, healthy, vibrant, delicious sauce.
(See SS w Tomato Sauce for a "fresh" tomato sauce, which expresses the flavor of the olive oil and is best made in August when tomatoes are at their peak.
Canned tomatoes using fresh tomatoes from Fahnestock and Rineer Family Farms (Saturdays at Rittenhouse Square) - we canned these in July and August using salt, lemon juice, and basil
Basil from Filter Square
Garlic from Highland Orchards at Filter Square
Smash garlic cloves with a large chef's knife and remove the skin.
Heat oil in large frying pan (w lid) and add garlic cloves. Immediately turn down heat and let garlic cook as you prepare the tomatoes. Add basil leaves.
Since we removed the seeds before canning the tomatoes, the entire jar can be dumped into a blender (remove the basil leaves) and pureed. If there are seeds, tomatoes should be put through a Foley Food Mill to remove the seeds and create a smooth pureee. [If you use factory canned tomatoes (from tin cans), drain liquid and run through the blender with fresh water.]
Add tomato puree to pan and turn up heat to bring to a low boil. Add water to create a runny sauce and cover, stirring frequently.
If you have an hour, keep the sauce at a steady boil and add water periodically. If you have 2-3 hours, keep the sauce barely simmering and cover completely. Keep tasting the sauce to understand how it changes over time.
My taste test:
At 15 minutes: sauce tasted like a fresh tomato but with a lot of acidity
At 1 hour: sauce tasted like a canned tomato puree, uncooked but with less acidity
At 1.5 hour: sauce tasted like tomato juice, cooked but still not ready
At 2 hours: sauce tasted like tomato sauce, but not quite ready
NOTE: Many people add sugar to their tomato sauce to balance out the acidity. I believe this can be achieved by cooking your sauce longer and using tomatoes that are of medium acidity. If you really like the flavor of sweet sauces, sauce onions with the garlic long enough so that they both caramelize and then run the entire sauce through the food mill at the end. Onions have a lot of natural sugar that will sweeten the sauce.