Run by the famous Fortran family, who also owns the older, much appreciated restaurant Al Cason in Mestre, the Osteria al Cason is located between San Tomà and the Frari Basilica, a little bit hidden in the maze that are the Callis of Venice.
The speciality of the house is the fish, always fresh and coming from the local area, cooked with seasonal vegetables. Among the many specialities, some that I recommend you try are the appetizer made with raw red snapper, shrimp and clams, the appetizer of mussel and clams, the spaghetti Buranella, prawns cooked with white wine and rosemary, and of course the fish dish of the day (always for two).
The Ostaria offers also some typical fish cicchetti like stockfish, or sarde in saor (sardines cooked with onions, raisin and pine nut) or octopus and options of meat such as chicken and pan-cooked tripe.
The restaurant is perfect for couples: even if you book only a few hours in advance you will be able to have a beautiful tiny white table outside on the fondamenta, decorated with candles and lanterns which I think give off a beautiful romantic atmosphere!