The filet, medium rare, and a Slurpee

Convenience-store sandwiches tend to look like 16-inch softballs—bulging masses of cheap bread, congealed meats and limp lettuce wrapped so tightly and thickly in cellophane that it’s difficult to make out what’s inside. That won’t do, given the growth of gourmet sandwich shops and people’s burgeoning ability to pronounce focaccia even in the hinterlands of America. 7-Eleven, as part of continuing efforts build a reputation for decent food, is touting its team of corporate chefs who are busy working on “new