Iwaen Kasumigaseki

Iwaen on the 2^nd floor of the Kasumi Dining building on the grounds of the Kasumigaseki Building is one of my all-​time favorites.
I used to office across the street during my previous stay in Tokyo, and was often reputed to drag my friends across the footbridge for some world class «Tan Tan Men» or Mapo Tofu.
The place is run by a nice elderly guy who could pass for Ed Sullivan in terms of looks, voice and mannerisms. The some of the server staff have worked their for years, as in at least 6 years, and they almost always know exactly what I want.
A bit of advice to the gaijin though, avoid the 11:52am to 12:43pm time frame at lunch because they queue stretches back to the escalator on the 2^nd floor. Of course, if you are Japanese, just stand in the queue for 45 minutes so, as doing so either makes your lunch taste better or gives you something to tell your friends about :).
There another Iwaen just up the road toward Akasaka at the street level.
You’ll be glad you eat here.