If chocolate is your thing you might want to visit this bakery in Lisbon that goes by the unpretentious name of "the best chocolate cake in the world". It does in fact seem to be springing up all over and has shops in several international cities. I have to say chocolate is not quite my thing but this cake is very good and many of my friends in Lisbon swear by it. They also serve a cheesecake but you can get better cheesecake elsewhere.
Service can be a bit useless but it is a small bakery with two tables for coffee so only really matters if you want to stay and be served.