Courtesy of Nick Stellino’s Glorious Italian Cooking 
Makes 5 3/4 cups
Pour the oil into a 3-quart pot on medium-high heat and cook the garlic and onion for
3 to 5 minutes. Reduce the heat and simmer and cook until the onions are soft and start to brown, about 10 minutes, stirring occasionally.
While the onions are cooking, put the tomatoes and their juices in a blender or food processor and purée until smooth. Add the tomato purée to the onion mixture, raise the heat to high and bring to a boil for 5 to 8 minutes. Reduce the heat, add the basil
and simmer for 25 minutes, stirring occasionally.
Cook’s notes: This is a plain, unsalted sauce which is great as an ingredient in other finished sauces, like Bolognese Meat Sauce . If you want to use this as a garnish for your pasta, add sea salt  to taste. Note that the recipe could be halved depending on how much you need or what you’re using it for.