It's been over a dozen years since I first had this perfect summer dessert while researching my KAFFEEHAUS book in VIenna. At Hans Diglas's cafe, one of the most venerable spots in the center of the city near St. Stephen's, I saw a big tray of layered cake in an old-fashioned metal baking pan, topped with red currants and meringue. Hans shared the recipe for the book, and I adapted it for more readily available blueberries. Is this the perfect Fourth of July dessert? I think so!