Position rack in center of oven and preheat to 350°F. Line baking sheet with parchment paper. Sift flour, baking powder and salt into medium bowl. Mix sugar, melted butter, 3 eggs, vanilla extract and ground aniseed in large bowl. Add flour mixture to egg mixture and stir with wooden spoon until well blended. Mix in almonds.
Divide dough in half. Using floured hands, shape each dough half into 13 1/2 inch long, 2 1/2 inch wide log. Transfer both logs to prepared baking sheet, spacing apart. Whisk egg white in small bowl until foamy. Brush over top and sides of each dough log.
Bake logs until golden brown (logs will spread), about 30 minutes. Cool logs completely on sheet, on rack for about 25 minutes. Maintain oven temperature.
Transfer logs to work surface, and discard parchment paper. Using serrated knife, cut logs on diagonal into 1/2 inch wide slices. Arrange slices, cut side down, on the same baking sheet. Bake for 12 minutes. Turn biscotti over, bake until just beginning to color, about 8 minutes. Transfer to rack and cool. Store in airtight container at room temperature.