The annual battle to capture the mooncake has been going on since August. This year the brands played more tricks with their packaging to lure younger consumers.

Xinghualou, a time-honored mooncake brand, decided on a makeover for its packages to attract more young buyers. Chinese moon goddess Chang'e, ambassador on Xinghualou's mooncake packages since 1933, now looks more modern and the new boxes are available only online.

"Online consumers are young. The old Chang'e is a classic legend, but we wanted to attract young people's attention. So we photoshopped the classic Chang'e," said Zhi Jing of Xinghualou. 

Xinghualou is not the only bakery working on upgrading the mooncake boxes. Haagen Dazs is doing cross-over marketing with a Spanish architect to make boxes decorated with mosaics. The ice cream maker is working with China Aerospace Science and Technology to launch special mooncakes that look exactly like the moon.

"Young people like new things. Post-90s are more online. So we sell some online special item and flavor," said James Chiu, managing director of General Mills, the parent company of Haagen-Dazs.

The latest JD.com report showed that almost 65 percent of modern mooncake buyers are post-90s, for whom "fun" is the number one reason to purchase mooncakes.

Meanwhile, JD's report also showed that tailor-made mooncake gift boxes account for more than 60 percent of the sales on its platform.

"You still have to make them taste good, but how customers react is important," said Alex Shutter, partner of Oliver Wyman, a leading international management consulting firm. "The majority of the mooncake purchased will be gifted to families, friends and colleagues. When you are giving the gift, the most important moment is the reaction from the people who receive it."