The slogan says "New York's famous hot dog" - Who knows, maybe it's truth :)
You can try it - "Hr. Smirnenski" street, in front of the University of Architecture and Civil Engineering and Geodesy.
The picture is not from Sofia, I captured it during my long weekend in Veliko Tarnovo. The sign on the street was inviting, but in the yard the store was closed. I was curious to feel the totally air-conditioned book-space, but ........ :(