Simple Tomato Sauce with Onion & Butter

I plucked this recipe from Smitten Kitchen about a year ago and have planned to make it ever since.  So with yummy summer tomatoes just right around the corner, I thought it the perfect time to give it a try.  It was simple and fresh and delicious.  I think the secret is its simplicity...there aren't spices that are overpowering the essence of the tomato flavor.  On our second trip to Italy, John & I ate (with Spencer & Kristi) at a little restaurant  in Rome (located on a side street with a direct shot at the Coliseum).  I had a simple pasta with tomato sauce.  There weren't lots of spices or other things complicating the dish.  Just pasta with tomato sauce.  It was incredible.  This sauce is the closest thing I have ever found to that.  I literally could not stop eating this. 

Ingredients:

28 ounces (800 grams) whole peeled tomatoes from a can (San Marzano, if you can find them)*
5 tablespoons (70 grams) unsalted butter
1 medium-sized yellow onion, peeled and halved
Salt to taste

Directions:

Put the tomatoes, onion and butter in a heavy saucepan (it fit just right in a 3-quart) over medium heat. Bring the sauce to a simmer then lower the heat to keep the sauce at a slow, steady simmer for about 45 minutes, or until droplets of fat float free of the tomatoes. Stir occasionally, crushing the tomatoes against the side of the pot with a wooden spoon. Remove from heat, discard the onion, add salt to taste (you might find, as I did, that your tomatoes came salted and that you didn’t need to add more) and keep warm while you prepare your pasta.