• In a large saucepan, over medium-high heat, melt butter.
• Add onions cut side down and a couple pinches of salt. Simmer for a couple minutes, but do not allow butter to brown.
• Using your hands, crush whole tomatoes as you add them to the pan. Reduce heat to low or medium-low to maintain a gentle simmer. Cook sauce for 45 minutes to an hour until droplets of fat appear on the surface of the sauce.
• Remove onions. Taste and add additional salt if necessary. You can use an immersion blender to puree the sauce or you can leave it chunky.
• Serve over hot pasta with freshly grated Parmesan and a bit of black pepper, if desired. Makes enough sauce to dress approximately 3/4 to 1 pound pasta.
• Optional: Dice or cut the cooked onion into wedges and add back to sauce before serving over pasta for a little added sweetness.

Variations:

• This recipe can serve as a nice base for building other flavors into an Italian sauce including adding fresh basil and garlic or dried oregano or Italian seasoning. Add chopped fresh garlic, dried oregano or Italian seasoning with the onion. Add fresh chopped basil at the end to finish the sauce.
• If you want to make a chunky, garden-style tomato sauce, sauté any combination of diced celery, green bell pepper, zucchini, and mushrooms in butter in a separate saucepan while the sauce cooks. Add back to the finished sauce with diced cooked onion.
• For a meat sauce, in a Dutch oven, heat a couple tablespoons of olive oil over medium-high heat. Add 1/2 to 1 pound ground beef or bulk pork sausage. Brown meat and then drain off fat. Add cooked meat to finished sauce.