I'll be headed to these two cities at the end of this week.
A recent search of the board gave me these recommendations. (sorry that I don't have correct attribution.) Are there any up to the minute comments?
Leonor Cava y Cana (or Cana y Cava) for the best ceviche
Astrid y Gaston (Fancy Peruvian)
Club Colombia in the Zona Rosa (high-end Colombian)
Harry Sasson in the Zona Rosa