Ingredients
Instructions
- Combine the tomatoes, their juices, the butter, and the onion halves in a medium saucepan.
- Add a pinch or two of salt. Place over medium heat and bring to a simmer. Cook, uncovered, at a very slow but steady simmer, adjusting the heat as necessary, for about 45 minutes, or until droplets of fat float free from the tomato.
- Stir occasionally, mashing any large pieces of tomato with the back of a wooden spoon. Taste and salt as needed.
- Discard the onion.