Как есть (a play of words: either “How to eat” or “As is”). Trekhprudny pereulok 11/13, stroyeniye 2. If you need to impress, either yourself or others, especially your new Russian g/f, that the sort of place.
The most “authentic” and also very inexpensive establishment with practical opening hours is the cafeteria at the Old Believers village (Metro Ploshad Ilyicha or Aviamotornaya). See http://where.cheap-moscow.com/my-favourite-places-to-eat-and-drink/. But it is there to provide food rather than self-esteem.
In this post-apocalyptic world images, values, and associations are of greater significance than what used to be called “real”. See elsewhere about my favourite religious sect that denies reality to just about anything, and holds ceremonies around a vacuum container.