The Broken Cake is an item that can be obtained in the Field by examining Top Chef's destroyed cake. It was commissioned by a Hathy for Clover's birthday party. However, Susie ate part of it, causing it to be broken.
If the party returns to Top Chef with the Top Cake, he is delighted that his cake has been repaired and asks them to give it back. If they choose to do so, he rewards them with one of his rejected cakes, Spin Cake, as long as they have room in their Inventory and are holding no other cake.
There exists an unused, consumable version of the Broken Cake (while the normal cake is a Key Item). If put into the normal inventory via save file editing, it heals 20HP to one party member. There is no dialogue from Susie or Ralsei when it is used.