What is Baumkuchen made of?

Context: Baumkuchen is a kind of spit cake from German cuisine. It is also a popular dessert in Japan. The characteristic rings that appear in its slices resemble tree rings, and give the cake its German name, Baumkuchen, which literally translates to "tree cake" or "log cake".

History
It is disputed who made the first Baumkuchen and where it was first baked. One theory is that it was invented in the German town of Salzwedel, which is further popularized by the town itself. Another theory suggests it began as a Hungarian wedding cake. In Ein new Kochbuch, the first cookbook written for professional chefs by Marx Rumpolt, there is a recipe for Baumkuchen. This publication puts the origin of Baumkuchen as far back at 1581, the year the cookbook was first published. Marx Rumpolt had previously worked as a chef in Hungary and Bohemia.

Characteristics

Baumkuchen baked on a spit
Traditionally, Baumkuchen is made on a spit by brushing on even layers of batter and then rotating the spit around a heat source. Each layer is allowed to brown before a new layer of batter is poured. When the cake is removed and sliced, each layer is divided from the next by a golden line, resembling the growth rings on a crosscut tree. A typical Baumkuchen is made up of 15 to 20 layers of batter. However, the layering process for making Baumkuchen can continue until the cakes are quite large. Skilled pastry chefs have been known to create cakes with 25 layers and weighing over 100 pounds. When cooked on a spit, it is not uncommon for a finished Baumkuchen to be 3–4 feet tall.

Baumkuchen ingredients are typically butter, eggs, sugar, vanilla, salt, and flour. Baking powder is not considered a traditional ingredient. The ratio of flour, butter and eggs is typically 1:1:2 respectively. The recipe can be varied by adding other ingredients, such as ground nuts, honey, marzipan, nougat and rum or brandy, to the batter or filling. Additionally, Baumkuchen may be covered with sugar or chocolate glaze. With some recipes, the fully baked and cooled Baumkuchen is first coated with marmalade or jam, and then covered with chocolate.

Answer: Baumkuchen ingredients are typically butter, eggs, sugar, vanilla, salt, and flour. Baking powder is not considered a traditional ingredient. The ratio of flour, butter and eggs is typically 1:1:2 respectively (i.e., 100 grams of flour, 100 grams of butter and 200 grams of eggs).