The most difficult red sauce I've ever made

This sauce has been floating around the internet hopping from food blog to food blog for years. I flagged it, since I'm so picky when it comes to red sauces and because it is so simple as far as ingredients. We have a favorite red sauce for Spaghetti, but there is just something refreshing about this Three Ingredient Sauce, apparently adapted by many from Marcella Hazan's Essentials of Classics Italian Cooking. I don't know how you can change much in a three ingredient recipe or adapt it. But there you go. I was blown away but this sauce, the butter just rounds out the tomatoes, cuts some of the acidity and gives the sauce some creaminess. The onions well, they just do their magic, there is just something about stewing them in the sauce that is wonderful. So simple and the ingredients are always on hand around here.

Now why was this so difficult for me? By nature I am a pinch of this, handful of that type of cook. I just add things and make things how I like them. Following recipes is difficult for me. It was tempting to toss in some garlic cloves, basil, anything to this sauce. But I decided I wouldn't change a thing no matter how many times I looked in the pot and though, just a dash of... I'm glad I didn't change a thing. That doesn't mean I won't ever change things around but this is perfect the way it is.

You can do a ton of things with this sauce. I served this over spaghetti noodles, but any pasta is fine. 

You can add some spices and simmer it down even further for a pizza sauce.

Add some cream to make it a creamy sauce.

Spoon over browned meatballs and simmer/bake in the sauce.

Slice summer squash toss with olive oil and spices layer in a baking dish. Spoon the sauce over the top and bake it. Sprinkle with Parmesan cheese. 

28 ounce can of whole/halved tomatoes

1 medium onion peeled and halved (I just had some quartered already, but halved will make your life easier)

6 tablespoons UNSALTED BUTTER (yes, butter- use it)

Kosher salt - I didn't use any but you might want to

That's it. Toss it in the pot. Bring it to a boil. Simmer for 45-60 min. Crushing the tomatoes with the back of a wooden spoon as it simmers down. Remove the onions and discard them. (Again I almost just whirled them in a blender into the sauce but, I took them out.) That's it. Seriously. EASY.