You don't see tomato soup cake on dessert menus at Michelin-starred restaurants. It's not a postmodern invention of the molecular gastronomy set. Unlike donuts or meatballs, it's not going through some upscale comfort food revival. Yet for the past century, tomato soup cake has endured, remaining a stalwart presence through decades of food trends to become an American dessert icon. And if you haven't tried it yet, you're in for a revelation.