I've just stayed some day alone in Lisboa. And to be honest, I don't like to go out for dinner by myself. That's way this time I won't have that many posts about restaurants in Lisboa, unfortunately. I spent the whole day working on new things for ToP and in the evening I was just happy to enjoy my hotel room at Casa C'Alma and micasaenlisboa. However, I did go out for dinner by myself once and even had wine. You should try out Graça do Vinho. It's also a lovely, cute and romantic place for a date with your beloved one. I had the plate with sausages (I don't know why but for once I was just craving for meat and not cheese). If you're two, I'd take the mixed platter. And I had the wine of the day which I don't remember anymore (excusez-moi).
Sorry for the bad quality, the light was not good in there.
As said cozy and romantic!