Lunch on Route 55 between Bloomington and Lincoln, IL
Bluestem Bakery is right off 55. Look for the Elkhart Illinois exit number 115 which is fifteen minutes north of Springfield. There is also a Tea House across the street. We always stop by the Bluestem on the way to and from Chicago. Summer hours open Thursday to Sunday.
Agree with Bluestem but call ahead to make sure they are open. Worth a stop just for cookies or if they have cinnamon rolls, they are the best. If you are not absolutely set on the geographic parameters in the OP, then there are quite a few places to recommend just a little south of there. If Bluestem isn't open try Blucat in Williamsville. Let us know if you would consider these recs.
900 Westport Road, Kansas City, MO 64111