I was in Stockholm last August and I can recommend one restaurant above all:
Stallmastergarden,which is located in the southern portion of Haga park,in
the north of Stockholm.
The quality of food was very good, the setting was outstanding. We had
dinner in the garden,under a huge gazebo, on the shore of the bay of
Brunnsviken, in the varying light of sunset.
In the cooler months dinner is served inside. The restaurant has been there
since the XVII century.
Tel 6101300, price about 45 USD per head.
Have a nice time in Sweden,
Leonardo from Italy