A tomato sauce that works beautifully with your favorite pasta or flatbread
Blend tomatoes in blender to desired consistency. I prefer my sauce smoother. You certainly can leave them whole and crush them right in the pan with the back of a wooden spoon. Peel onion, cut in half, trim shaggy roots and add to the pan. Add the butter a little salt and pepper (about 1 tsp of salt and maybe 1/2 tsp of pepper to start). Simmer for 45 minutes uncovered until the fat starts to separate from the tomatoes. Adjust seasonings with salt and pepper. Of course, you can add red pepper too!
So versatile. Add crushed red pepper, fresh basil but keep it simple.