The traditional version consists of multiple layers of chocolate sponge cake with whipped cream and cherries, covered on each side with whipped cream and chocolate chips, as well as with cherries on top. Traditionally, the recipe includes Kirschwasser, also known as "Kirsch," a type of cherry liqueur similar to brandy.
The dessert made its first "official" appearance in a cooking text during the 1930s and began to enjoy much popularity after World War II. However, there are two stories that trace the origins of the Black Forest Cake.
The first story is that of Josef Keller, manager of the Café Agner in Bad Godesberg - once an independent municipality and now included in the urban district of Bonn. Keller reportedly invented this cake at his restaurant in 1915.
According to a second story, the dessert came from the Black Forest in the mountainous area of Baden-Württemberg, where cherry trees planted by newly married couples abound.
Naturally, Black Forest cake is popular in Germany but it is also considered a traditional dessert in Austria, Switzerland and Italy (especially in the northern region of Trentino Alto Adige).
Practically identical in its appearance, in these countries, the Black Forest cake is prepared with few, if any, variations: in all three it is very common to use dark wild cherries (which are a bit sour in flavor).
One differentiating feature is the use of Kirsch. This alcoholic ingredient can be replaced by rum - especially in the version prepared in neighboring Austria - or directly omitted (as happens in certain Swiss and Südtirol regions).
According to finedininglovers.com