Whisk the flour and baking powder in a bowl to blend. By hand or with a mixer, beat the sugar, butter, vanilla and anise extract, and salt in a large bowl to blend. Beat in the eggs 1 at a time. Add the flour mixture to the wet mixture and beat just until blended.
Form the dough into foot long, 3-inch wide logs on a prepared baking sheet. Bake until light golden, 30- 40 minutes in a 350 degree oven. Cool for 30 minutes.
Place the log on the cutting board. Using a sharp serrated knife, cut the log on a diagonal into 1/2 inch-thick slices. Arrange the biscotti, cut side down, on the baking sheet. Bake the biscotti until they are pale golden, about 15 minutes. Transfer the biscotti to a rack and cool completely.