Good suggestions above.
Also consider Cafe Spiaggia. Lovely Italian. Many seem to prefer it to it's more expensive big sister, Spiaggia.)
If there are steak-lovers among you, Capital Grille (http://www.thecapitalgrille.com), David Burke's or Custom House.
Farmerie 58 (www.farmerie58.com
David Burke's Primehouse
616 N Rush Street, Chicago, IL 60611
980 North Michigan Ave, Chicago, IL 60611
Custom House Tavern
500 S Dearborn, Chicago, IL 60605
Thank you, i got the days mixed up. Blackbird and Sepia both do not have lunch on weekends.
How about Atwood Cafe? It is an oasis in the middle of bustling State street. Or Shanghai Terrace. It is upscale Chinese that is not necessrily uniquely Chicago, but it is uniquely Peninsula.
108 E Superior, Chicago, IL 60611
1 West Washington St., Chicago, IL 60602