According to Official Guinness Records,
The largest dessert decoration lesson (single venue) consists of 2,095 people, achieved by MORINAGA MILK INDUSTRY CO., LTD. (Japan) at Tokyo Big Sight, in Koto, Tokyo, Japan, on 28 March 2018.For just over an hour, the participants learned how to decorate a cake with a cherry blossom motif from renowned pastry chef Hideo Yokota. The event was held to commemorate the 100th anniversary of MORINAGA MILK INDUSTRY CO., LTD., and the cake used in the attempt was titled "Minna de sakaso, mori no 100nen zakura," in Japanese, or "Let's make it bloom, the 100 year-old cherry tree in the woods," in English.
For a complete list of 2018 records, please visit 2018 Guinness Records in Japan.