Use this sauce to make our Grilled Margherita Pizzas.
Crush tomatoes with your hands in a large bowl. Heat oil in a large skillet over medium heat until hot but not smoking. Add crushed tomatoes, oregano, salt, and pepper, and reduce heat to medium-low. Cook, stirring occasionally, until thickened, 40 to 50 minutes.
Pass sauce through a food mill into a bowl; discard solids. (Alternatively, process sauce in a food processor until smooth.)
If not using immediately, refrigerate sauce in an airtight container up to 1 week or freeze up to 1 month.