The Shining Baumkuchen is a dessert found at the 50th (final) floor of Mt. Gelato's Mine. Despite the Shining Baumkuchen being a dessert, it is impossible to eat it. However, it can be given to people as a gift (everyone loves it as a gift), or it can be shipped for 2000G.
However, you can only get a Shining Baumkuchen once. If you go to the 50th floor after obtaining it, you will not find another Shining Baumkuchen. If you are trying to impress a bachelor/bachelorette, it is a good idea to give it to that person. Otherwise, ship the Shining Baumkuchen for 2000G.