Anyway....
as a lot of CBF members are going to Istanbul this year then my mum says that the coffee at Kahve Dünyasi (Coffee World) a Turkish franchaise is the business!
There don't appear to be addresses of the branches on their web site but there is one very close to the Grand Bazaar and another virtually opposite the Kabitas tram line (not sea side).
You get given a bowl of milk/bitter and white chocolate covered coffee beans (there may be some pistashios in there too).
Cakes are really yummy and they also sell loads of super chocolates and have a range of iced coffees.
http://www.kahvedunyasi.com/default.aspx