Tomato Butter Sauce (Rod Stafford)

A Story
This is the red sauce I make, Julia makes, and Laura makes. We learned it from Cathy Whim of Nostrana, at a fundraiser for an agency Molly used to work for. She learned it from Marcella Hazan who created the recipe. It could not be simpler - three ingredients - and it could not be better

A Recipe

1 28oz can of good quality tomatoes, preferably San Marzano, plus juices
1 onion, peeled and cut in half
1 cube butter (or 5 tablespoons if that sounds like too much)

To a sauce pan, add the tomatoes and juices (crush the tomatoes in your hand), the onion halves, the butter, and a pinch of salt. Bring to a slow simmer and let cook uncovered for 45 minutes, stirring occasionally, until the fat starts to separate to the top. Add salt to taste. Discard the onion before serving. Makes enough sauce for one pound of pasta.