Unbirthday Cake

The Unbirthday Cake appears as a traditional vanilla sponge cake adorned with intricate floral patterns. However, upon consumption, it triggers a unique temporal anomaly where the eater's birthday becomes forgotten – replaced by an arbitrary date ranging between January 15th and April 22nd. As such, the individual will begin experiencing unseasonal nostalgia towards summer solstices instead. This phenomenon lasts until another slice of Unbirthday Cake is ingested within the same lunar cycle. The flavor profile remains consistent throughout, described as 'softly whipped cream.'