When I used to work near Northwestern Hospital, I loved their Spice of Life Cafeteria (operated by the Morrison's chain) on the second floor -- fresh, cheap, with lots of separate chef stations and plenty of seating. The Equitable Building also has a nice operation on the lower level. Are they the last of a dying breed? The huge Sears Tower American Cafe is long gone; the second-floor Aon Building cafeteria was a victim of post-9/11 security (although they have a passable replacement on the concourse next to Starbucks), and the downtown colleges have replaced their cafeterias with tiny snack bars/deli counters. Are there any "hidden" places any more where outsiders are welcome without having to bother with building security?
"Yankee bean soup, cole slaw and tuna surprise."