- 1 (28-ounce) can peeled plum tomatoes, no salt or herbs added
- 5 tablespoons unsalted butter
- 1 small white onion, peeled and cut in half
- Kosher salt
- Wash your hands.
- Put a 3-quart saucepan over medium-high heat. Add the tomatoes, butter, onion halves, and a pinch of salt. Bring to a simmer, and then lower the heat.
- Crush the tomatoes lightly with the back of a spoon as they cook, and stir occasionally. Simmer very gently for 45 minutes, or until droplets of fat appear on the surface of the tomatoes. Remove and discard the onion.
- Serve over hot pasta with Parmesan and black pepper, if desired.