This D.C.-based burger joint in the Loop has 10-plus tempting milk shake flavors, but none—here or anywhere, for that matter—compete with the toasted marshmallow one. Fluffy pillows of sugar are roasted with a culinary torch and blended with house-spun vanilla ice cream till all that’s left is their smoky essence and bits of char. Garnishes of whole marshmallows and otherworldly whipped cream prove anything but superfluous. When something tastes as mind-numbingly delicious as this, you must pause and give it its due. (But get in line first.) 22 S. Wabash Ave., 312-854-3027