This cake is actually known as Zwetschgendatschi in Bavaria, where it is most popular. Roughly translated from Bavarian to German, it would be called Pflaumenkuchen or plum cake in English. BUT Zwetschgen aren't ordinary plums, a Datschi isn't really a Kuchen, and a Kuchen is most definitely not a cake! Or at least not a tall, spongy cake -- it's flatter. Ideally, for this dessert you want the slightly tart Italian plums. If you do have to use another type of plum, be careful the variety you choose isn't too juicy.