Tuna-noodle may well be the great American casserole. Cheap, nourishing and easy to make in bulk, it's a staple of school lunchroom cooks and moms with smaller but no-less voracious crowds to feed at home. Prepared with canned fish, condensed soup and potato chips, it is, on the other hand, not exactly what one would call fine dining. And yet, as a concept ("seafood and pasta gratin with mushroom sauce"), it sounds almost restaurant elegant. And so it ends up in this fully-tweaked version, complete with fresh poached salmon, white wine and imported pasta. Serve it at a dinner party (but don’t refer to it as a "casserole") and your guests will be dazzled.
