In Italian markets, in season, you will find ripe tomatoes on sale specifically for sauce. They are locally grown and newly picked, and are called pomodori da sugo. They are full of natural elements such as vitamins and, because they are ripe and not acid, they are ideal for sauce. This basic tomato sauce is used for a variety of purposes: for a ragù, for pasta, for soups and potatoes, etc. Personally I like it very simply served, with lovely spaghettini and a scattering of basil leaves.