As Lulu said, mooncakes are sweet, rich, heavy and dense pastries sometimes filled with salted duck egg yolk. They come with assorted fillings such as the traditional lotus seed paste, red bean, black bean, and green bean paste and in recent years, yam and durian paste. Another version is snowskin using fried glutinous rice flour for the skin. They are shaped either round or square and are usually eaten during the Mid-Autumn Festival which this year falls on 25 September. On this day, the moon shines brightest and fullest, the 15th of the eighth moon in the lunar calendar.
In celebrating this festival, families gather under the silvery moonbeams to enjoy mooncakes washed down with fragrant Chinese tea while kids and the young-at-heart enjoy walks with lanterns all aglow. Legend has it that mooncakes helped bring about a revolution during the Yuan Dynasty (AD 1280-1368) which was established by invading Mongols from the north. Secret messages detailing that the rebellion was to take place on the 15th night of the eighth moon were placed inside mooncakes instigating people to revolt against the Mongols. After the rebellion, the Ming Dynasty was born.
Every year I make it a point to bake such goodies for DH's family, relatives and friends. Needless to say, it takes a lot of work and skill to master the art. Mooncakes are usually sold in Chinese restaurants and hotels and fetch a high price during the festival.
To share with fellow DC members, below is a picture of mooncakes I made last year.