Cafe Einstein is a very old coffeeshop and restaurant chain in Berlin. Their “Stammhaus” is in Kurfürstenstrasse (don’t confuse with Kurfürstendamm!). They are Austrians and offer Austrian Specialities in a high quality at an acceptable price. Coffee is in any branch good. “Unter den Linden” is the main touristic road that leads from Brandenburger Gate to the Museum Island and passes most historical places.
Cafe Einstein is liked by all, Tourists as well as Politicians as Reichstag and the Office buildings are close by. Not only in the back room you see very often at weekdays important politicians taking their lunch or having a coffee. Staff is friendly and helpful with everybody.
It is also a restaurant and i.e. their Wiener Schnitzel is acceptable (that means pretty good).
On the photo the Apfelstrudel of my wife looks so small, but it is gigantic. Taste is good, a bit sweet may be. My croissant was not that big.
I prefer the Stammhaus in Kurfürstenstrasse. It has a good ambiance and is less pricey (Apfelstrudel is only 7,50). Also it is easier to park. But if I show friends Berlin I am always happy to make a stop at the Einstein.