Perhaps no city has embraced the casual trend in dining like Chicago. But when one considers how dining trends often run amok--the way Cajun did in the '80's--could casual dining fare much better, particularly in a town that's breeding restaurants with names such as Ketchup and Relish? It's too early to say, though it must be pointed out that Ketchup couldn't cut the mustard (sorry) and quickly closed, while Relish has added more than a little zest to Chicago's dining scene. Ron Blazek's Relish embodies the best of casual by blending informality with sophistication: he offers a BLT, for example, which features seared scallops, arugula, pancetta, and pine nut aioli. The 29-year -old's style comes in part from the renown Gordon, where he was most recently executive chef. Relish's casual whimsy is pure Blazek, who's a hot dog at heart.