baumkuchen
German for "log cake" or "tree cake". A layered cake baked on a spit, which gives it its hollow circle design. When sliced, the layers make the cake resemble tree rings.
It is popular in Japan including because it is a popular return present for wedding guests because of its ring shape, similar to the symbol of the Zen Enso symbolizing good luck. Karl Joseph Wilhelm Juchheim introduced it to Japan at a 1919 German exhibition in Hiroshima, and two years later, he and his wife founded the Jochheim Company, which continues to sell baumkuchen and other sweets according to Juchheim's original recipe in pastry shops throughout the country.