Wash the tomatoes and roughly cut them into pieces, I only cut them in half. Add vegetable salt and puree well in the blender. Since the Vitamix has a function that heats the sauce when it is pureed for a long time, it doesn't have to be put in the saucepan again :-) It also tastes warm and so the vitamins are retained, because many of them are lost when heated to 40 degrees.