Beat egg yolks, powdered sugar and salt in a large bowl until pale and creamy. Beat egg whites until very stiff; fold into egg yolk mixture. Siftflour, baking powder and aniseed onto egg mixture; fold in quickly but thoroughly. Fill a pastry bag fitted with a plain nozzle with cookie mixture. Pipe in small rounds onto prepared baking sheets. Let stand overnight to dry out.
Preheat oven to 325 deg. Bake cookies 20 minutes. Cool on rack.