Bad Ischl in Upper Austria was the favorite summer spot of Franz Josef, and therefore of the entire blue-blooded population of Vienna. (One of the best bakeries in the world, Zauner, is located in Bad Ischl, and there’s nothing like having an emperor as your best customer to ensure quality control.) These large, crisp sandwich cookies, filled with preserves and glazed with chocolate, became popular with vacationers, who took them back home and thereby spread their popularity. The tartlets are now firmly ensconced in the cookie selection of every bakery along the Danube. Sometimes they are filled with a chocolate buttercream, but I love the contrast between the tart preserves and the sweet chocolate glaze.