Beat eggs in a large mixing bowl until thick and lemon colored; gradually add sugar and butter; continue beating 10 minutes. Stir in anise.
Combine flour and baking powder in a medium mixing bowl; stir well. Add to egg mixture, stirring well.
Roll dough to 1/8-inch thickness on a lightly floured surface. Use a floured cookie mold or springerle rolling pin to imprint dough. Separate cookie squares using a knife. Place 2 inches apart on well-greased cookie sheets. Let stand, uncovered, in a cool, dry place 12 hours or overnight to set design.
Bake at 300° for 12 to 15 minutes. Remove from cookie sheets, and cool on wire racks.