A donut nectarine, also known as a Saturn peach or flat peach, is a variety characterized by its flattened, disc-like shape with a slight indentation resembling a donut. It has smooth skin that ranges from yellow to red-orange, and its flesh is juicy, sweet, and low in acidity. Donut nectarines are typically larger than traditional nectarines and are prized for their unique appearance and delicious flavor, making them popular for eating fresh, in salads, or in desserts.