Mix butter with flour, confectioners' sugar and lemon peel until combined. Divide dough in half; on floured surface, roll each half to a 6" long cylinder. Wrap each half in plastic wrap; refrigerate 1 hr. Preheat oven to 325. Grease large baking sheet. Cut each roll of chilled dough crosswise in 1/2" thick slices. Place cookies cut side up, on prepared baking sheet. Bake 12 min at 325 or until top of cookies are firm to the touch and are lightly browned on the bottom. With spatula remove to wire rack. Sprinkle cookie with additional confectioners' sugar before serving. ----