Easy Marinara Sauce

Ingredients

5 tablespoons unsalted butter 

1 teaspoon salt

1 medium onion, sweet onion preferred, peeled and cut in half

1 28 ounce canned whole peeled San marzano tomatoes with its juices

Directions

1. Crush the tomatoes wit your hands.
2. Put the tomatoes, onion, butter, and salt in a 4- to 5-quart saucepan over medium heat. When the tomatoes begin to bubble, lower the heat to a slow but steady simmer. 
3. Cook, stirring every 10 to 15 minutes, and breaking up the tomatoes with a wooden spoon.  Cook until the tomatoes are no longer watery and the sauce has reduced, about 45 minutes. The sauce is done when the butter has separated from the tomatoes and there is no remaining liquid.
4. Remove and discard the onions.
5. Toss with cooked spaghetti and add grated Parmigiano.

Notes:

You may add a tablespoon or two of tomato paste if you want to thicken the sauce.

You can brown a couple of garlic cloves in a little olive oil in the saucepan before adding the ingredients.

If sauce is too acidic add a carrot to absorb the acidity. Toss out the carrot when you discard the onion.

Brown some diced pancetta, or sausage with casing removed, or salted pork etc in olive oil before adding the tomatoes for depth of flavor.