In a large bowl, whip eggs and sugar together for 15 minutes on the high speed of an electric mixer. Gradually stir in the flour, anise oil and anise seeds. Spoon out dough by rounded teaspoonfuls onto well greased cookie sheets. Decorate at this time if desired. Let the cookies stand uncovered for at least 4 hours.
Preheat the oven to 300 degrees F (150 degrees C). Bake cookies for 12 to 15 minutes, until cookies begin to brown. remove from baking sheets to cool on wire racks.