1Position 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.
2Mix sugar, melted butter, 3 eggs, vanilla extract and ground aniseed in large bowl.
3Add flour mixture to egg mixture and stir with wooden spoon until well blended. Mix in almonds.
4Divide dough into thirds. Using floured hands, shape each dough third into a 10 inch-long, 2 1/2-inch-wide log on prepared baking sheet keeping a 2’’ space between logs (logs will spread). Whisk egg white in small bowl until foamy; brush over top and sides of each dough log.
5Bake logs until lightly golden brown w/ surface cracks on top, about 30 minutes.
6Cool logs completely on the sheet pan on a rack, about 25 minutes. Maintain oven temperature. Transfer logs to a cutting board; discard parchment paper. Using serrated knife, cut logs on diagonal into 3/4 inch slices. Arrange slices, cut side down, on the same baking sheet. Bake 16 minutes. Turn biscotti over; bake until just beginning to color, about 10 minutes. Transfer to rack and cool. (Can be prepared 1 week ahead. Store in airtight container at room temperature.)