Here's a simple and very classic dish from Naples. There are very few ingredients, so quality is of top importance. I call here for top quality canned tomatoes: that's because the best brands have a reputation to maintain, the tomatoes are ripe when they are canned, so they are far better than "fresh" supermarket tomatoes in January in New England. Of course if you can get farm-fresh tomatoes in August and September, by all means use them! But the rest of the time you will probably be happier with canned tomatoes from an excellent producer. The onion, cheese, and basil must also be of good quality, and that's about all there is to this sauce.
Of course it's best served on high-quality pasta, too, which means for a Neapolitan recipes you want Pasta di Gragnano if you can get it.