Prinzregententorte (Bavarian Layer Cake) vs Classic German Chocolate Cake

Both cakes lean on cocoa, sugar, butter and eggs, yet they use them in very different ways. The Prinzregententorte stacks eight thin, quickly baked cocoa sponges with a buttercream made by beating a cooked vanilla pudding into creamed butter, then deepened with cocoa and optional rum; a brush of apricot jam and a glossy dark chocolate and cream glaze finish it. The German chocolate cake uses two thicker oil-and-buttermilk layers, filled and topped with a cooked evaporated-milk and egg-yolk custard studded with coconut and pecans.