A gorgeous, sticky and sweet chocolate cake that my friend Kati made for my birthday this year! This is a Russian recipe that uses sour cream in the batter - no butter, no margarine, no oil, but let's just say that the cake is still not exactly light!! Also, note that the cake recipe is for one cake: you need to make two for a nice, tall cake. Do NOT double the cake recipe - make it twice! If you want to make a smaller "Prague torte", make just one cake and halve the syrup and filling ingredients. The original recipe was somewhat vague instruction-wise (make cake, bake until done, sort of thing...) but this is how Kati ended up making it - and it was luscious!!