I've read that it is also a tradition to hide a bean in the cake - and whoever finds this bean is king for one day!
These two pics below show cakes with a similar recipe and are called "Couronne" (crown or wreath, both translations would make sense...)
The French have another Epiphany cake called "Gallette des Rois" (Kings'cake) which is also sold in Geneva. It has an almond filling. Check out a recipe here.