Saturn Peach, Saucer or Peento Peach
The donut peach is a descendant of the flat peaches of China. First grown in America in the 1800's. The name was derived from the appearance, which looks like a cake donut. The peach is approximately 1 to 2 inches in height and 2 to 3 inches in diameter. The skin is pale yellow with a red blush. The pit (free-stone variety) is about the size of a pistachio nut. The white flesh is tender, juicy, and sweet tasting, similar to a nectarine. The peach has a low acid to sugar ratio, so it is sweeter than the orange flesh variety. It is an excellent addition to salads, desserts, crepes, and other dishes requiring fruit.
Flat peaches originated in China, and were first grown in the U.S. in the 1800's. Somehow it fell out of favor. Perhaps that was due to its white flesh. Earlier American consumers preferred yellow fleshed varieties, so fruit breeders routinely discarded those with pale flesh.
Originally the flat varieties had no special names. They were just called Chinese flat peaches or Chinese saucer peach. They were also known as peento peaches. In Australia they're named saucer peaches. These names aren't catchy enough, so the marketing gurus apparently came up with the name 'donut peach.' And the marketing campaign was indeed a success. They're grown commercially in Central California and Washington.