Beat butter and sugar together until creamy. Add eggs, one at a time, beating well after each addition. Using a mortar and pestle, crush anise seed lightly. Add to creamed mixture. Mix well.
In a separate bowl, stir together flour, baking powder and salt. Add to creamed mixture, beating until smooth. Mix in nuts. Turn out onto a lightly floured board and shape into two flat loaves each ½-inch thick, 2-1/2 inches wide, and as long as the baking sheets. Transfer to greased baking sheets. Bake in a 375 degree oven for 20 minutes, or until lightly browned.
Remove from the oven and cool 2 minutes. Then slice ½-inch thick. Lay slices, cut side down, on baking sheets. Bake at 375 degrees for 10 minutes longer, or until just golden brown. Remove to wire racks to cool.