Combine first 5 ingredients and mix (or process in a food processor) until smooth. Add the flour and mix thoroughly, then shape into a cylinder and refrigerate, wrapped in waxed paper, for at least 2 hours. Preheat oven to 400 degrees F and slice dough into ½-inch rounds. Bake on ungreased cookie sheets for 5 to 10 minutes. Serve warm with soup or salad, or as a cracker for smoked salmon or other appetizers.