This requires the least work of all the cooked tomato sauces. With this technique, everything tomatoes, olive oil and seasonings goes into the pot more or less at once, usually with no presaute and simmers until thick. Instead of the distinctively layered tastes of saute-based sauces, the simmered sauce is softer, more tomatoey and mellow.
Slow roasting requires rather little effort for the succulent results that are produced. It concentrates the flavor of tomatoes, leaving them intact but meltingly tender.