The everlasting pleasures of liver and onions

There exists a fine line in cooking between “old school” and “retro,” and it seems to be delineated by nostalgia. Any foodstuff we can point to that has fond memories associated is “retro,” and a return to them is met with paroxysms of delight (Steak Diane, for example—it’s beef but with fire and theater!). Some “old…