San Marzano tomatoes are a prized variety of plum tomatoes known for their elongated shape, deep red color, and rich, sweet flavor with low acidity. Originating from the San Marzano region in Italy, they have a thick flesh with fewer seeds and are less watery than other tomatoes, making them ideal for sauces and canning. Their balanced sweetness and tanginess make them a favorite in Italian cuisine, especially for creating authentic tomato sauces.