Beat eggs until very light and fluffy. Gradually add sugar; beat for 15 minutes. DO NOT underbeat. Fold in anise extract and flour. Roll dough 3/8-inch thick. Thoroughly flour springerle mold or rolling pin. Press molds firmly to dough. Cut cookies apart and place on greased and floured cookie sheet. Let dry overnight at room temperture, covered with paper towels, or uncovered. Preheat oven to 375 degrees F. Place cookies in oven and immediately reduce temperature to 300 degrees F. Bake for 15 minutes. Cookies should not brown. Store cookies 2 to 3 weeks to mellow flavor. These cookies are very hard and may be used for dunking in coffee, tee or cocoa. For Christmas, paint designs with egg yolk colored with food coloring. Makes 6 dozen.