First of all, your server must win the A Piece of Cake event. After the next server save NPC will appear here :
Say help to him, then he will ask you to step on the Cake Base at the island, and then visit the Cake Extraction Machines in 5 cities. Once you have stepped on the extraction machine, return to the Cake Keep Isle, step on the cake base again and then proceed to the next city, repeating the proces for example : Cake Isle > Darashia > Cake Isle > Liberty bay > etc.
Once you have visited all the extraction machines, return to and ask for your reward.
Remember that you can only collect one of three prizes!