Slice of prinzregententorte - wikipedia.org
Prinzregententorte is a cake found mainly in Bavaria, which consists of at least six thin layers of sponge cake interlaid with chocolate buttercream. The exterior is covered in a dark chocolate glaze.
The cake is named after Prince Regent Luitpold, who was Prince Regent of Bavaria beginning in 1886. Its exact origin remains in dispute; among those claimed as its creators are the prince regent's cook, Johann Rottenhoeffer, the baker Anton Seidl, and the baking firm of Heinrich Georg.
Typically, the cake consists of very thin layers of sponge cake, each approximately 25 cm in diameter, with chocolate buttercream on each side. Apricot marmalade may be added to the topmost layer, and the whole is covered in dark chocolate.