Sift together the flour, salt and baking powder and set aside.
In a large bowl, beat the margarine/butter and sugar until light and fluffy. Beat in the eggs, one at a time, mixing until smooth. Stir in the flour mixture. Fold in the chopped walnuts and ground star anise until combined into the dough.
Shape the dough into 4 or 5 rolls that are the same length as the baking trays. Place the rolls onto ungreased baking trays, 5cm apart and flatten slightly.
Bake for 15 to 20 minutes in the preheated oven until just starting to brown. Remove from the oven and cool on wire racks. When the rolls are cool enough to handle transfer them to a cutting board. Using a serrated knife cut the rolls crosswise into 2cm slices. Place the slices on the baking trays and return to the oven for an additional 5 to 10 minutes until golden and crispy.