The Famous Butter Tomato Sauce

Here's another one of those super simple, only-three-ingredient recipes that I love.  I think I first discovered this recipe from Orangette, but it's also been posted by so many other people.  Gilt Taste speculates that it might be the "most-blogged about pasta sauce on earth".  I've even read about this sauce in a Nicholas Sparks book!

 
So when I saw that San Marzano tomatoes were on sale at Whole Foods (3 cans for $7!), I knew I had to get some cans and make this sauce again.

Marcella Hazan's Tomato Sauce with Onion and Butter (adapted from Marcella Hazan's Essentials of Classic Italian Cooking)
makes enough sauce to toss with 1 pound of dried pasta

1 28-oz. can of San Marzano whole, peeled tomatoes
1 small onion, peeled and halved
5 tablespoons butter

 
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 (this took me longer than 45 minutes).

Stir occasionally, mashing any large pieces of tomato with the back of a wooden spoon (be careful; I ended up squirting myself a few times with hot tomato innards!).

 
Taste and salt as needed.  Discard the onion before tossing the sauce with cooked pasta.

 
I actually washed the sauce off the onion and saved it in the fridge for the next time I needed to add softened onions to a dish.  If you want, you could just chop up the onions and throw them in the sauce, or blend them into the sauce, but I think the sauce is already perfectly balanced as is.  The only thing I would maybe add to the pasta is some shaved parmesan cheese.