More than six types of mooncakes are made for the festival, which falls in the middle of the eigth lunar calendar month. This is when the Chinese moon is fullest and largest. The mooncakes can be sweet or salty - an oil and molasses-sweetened pastry filled with duck egg yolks (symbolising the full summer moon), red bean, lotus seed paste or a plain molasses and flour filling for children. Each type is set in a patterned mould before baking.
Legend has it that in the time of the Yuan dynasty in China, an underground group led by Zhu Yuan Zang was determined to rid the country of Mongolian dominance. The mooncake was created to carry a secret message. When the cake was opened and the message read, an uprising was unleashed, which successfully routed the Mongolians. It happened at the time of the autumn moon, so that's why moon cakes are eaten at that time even to this day.