A tree ring cake with a long history in Germany has become quite popular in Japan, thanks to the culinary skills of a World War I prisoner of war. The cake is known as Baumkuchen.
German confectioner Karl Juchheim was among about 4,700 prisoners of war, mostly Germans, who were kept at 16 camps across Japan during World War I.
Juchheim came to be a prisoner of war after he was captured by the Japanese in 1915 when he was running a bakery in Qingdao, China. He arrived in Ninoshima, a 20-minute ferry ride from Hiroshima, in 1917. Ninoshima was a military quarantine station, and German prisoners of war there were allowed to cook.
The cooking that Juchheim did involved making Baumkuchen, a traditional type of German tree ring cake. It has other names too such as layered butter cake, spit cake, or king of cakes. The tree ring name describes the cake well, because it has so many layers that the finished cake looks like a series of tree rings. After the war, Juchheim remained in Japan, where he founded a pastry business called Juchheim Co., Ltd. Today, it is located in Kobe City with branches in several other Japanese locations. It still operates as one of Japan's top confectioners.
Baumkuchen has a long history, going back to ancient Greece. Roman soldiers spread knowledge about the cake to Europe. In Hungary, in the mid-1500s, it was called a traditional Hungarian chimney cake. A Hungarian chef published a cookbook in 1561 that included how to make the layered cake. In Germany, the cake got its official name, Baumkuchen. That information comes from the Glutto Digest, a food blog. You can find it at https://gluttodigest.com/Baumkuchen-japanese-german-spit-cake. There, you can find a recipe for the cake. Several other sites carry Baumkuchen cake recipes, but this site has the ingredients in cups, teaspoons and tablespoons rather than European style measurements.
It takes quite a long time to bake. The Glutto Digest blog recommends using a springform pan in which to spread half a cup of batter, which is then cooked under a preheated broiler for three to five minutes. Then another layer of batter is added on top of it and cooked for a few minutes. The process of adding and cooking batter continues for ten or more layers. The Glutto Digest blog describes the process well in case you want to bake a Baumkuchen tree ring cake yourself.
Kazuaki Otani, head of the Juccheim Ninoshima Welcome Center said that Juccheim used his baking to express his desire for peace. Baking a tree ring cake sounds like an interesting activity at Christmas time for people willing to take the time to make it. It is one way of honoring Juccheim's desire for peace.