I second or third Charlie Trotter's, but as they will be closed when you are there, you might try Zealous. The head chef and owner is a Trotter protege. I ate at both during a Chicago trip last year. Here's a link to the trip report if you want the details of the meals ... and don't worry, despite my trip report, there's a whole lot more at each restaurant than just veggies.
http://www.flyertalk.com/forum/Forum81/HTML/000980.html

[This message has been edited by letiole (edited 02-28-2001).]