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.