These crisp cookies are delicious in the middle of the afternoon when you want a little something sweet or served with a cup of tea. The thin, elegant wafers have a fine sandiness and a slight acidic earthiness that comes from the buckwheat flour. My husband, Thomas, had the idea to roll the dough in poppy seeds to add a little texture to the delicate cookie. The logs of dough can be formed and chilled or frozen ahead of time so that they’re ready when you need them. Using parchment makes it easier to lift these cookies from the baking sheet.