Heat the olive oil in a pan until hot but not smoking. Add the onion and the garlic and cook until the onion is
translucent, about 5 minutes.
If using whole tomatoes, crush them in your hands as you add them to the pan, then add the juices to the pan
as well. If using crushed tomatoes, add the entire contents of the can to the pan. Then add all the seasonings. Stir
to combine, bring to a simmer, and cover. Cook over very low heat for 30 to 40 minutes. If you prefer a thicker
sauce, remove the lid and cook for 10 minutes more to evaporate some of the liquid. The tomato sauce will be
cooked but should still be bright red in color.
Note: You can make endless variations with this sauce. Add dried thyme instead of oregano. In summer, chop
fresh basil and add it toward the end of cooking. Add a bay leaf or two for a sauce that will be used with beef or
pork. Or add dried chili flakes, about half a teaspoon, with the onion and garlic for a spicy version.