My guide I posted back is a bit outdated but has soe good recommendations
http://www.flyertalk.com/forum/europ...cow-guide.html

Pod Baranem (http://podbaranem.com/) is still my favorite Polish cuisine restaurant in the city. I love their beef tartare and their main courses are traditional Polish food.
Hawelka in the Rynek (some 20m from Hotel Stary) is also excellent for Polish food. They also have a great beef tartare and traditional Polish food.
In both restaurants I would recommend the mushroom soup. Both use a breadbowl and also both use wild mushrooms, which gives it a excellent taste.

If you want to try something unique:
http://www.tripadvisor.co.uk/Restaur...rn_Poland.html

also, if your in the Jewish Quarter, there are plenty of excellent Polish/Jewish restaurants to go to such as:
Klezmer Hois
Ariel
AWIW
The first 2 have live music (usually with a cover) every day - it's something different to experience.

Hope this helps!