Beat the first 5 ingredients at medium speed of a mixer until well-blended. Beat in egg whites. Lightly spoon the flour into dry measuring cups, and level with a knife.
Combine the flour, baking powder, and salt; gradually add flour mixture to sugar mixture, beating until blended. Stir in almonds.
Turn biscotti dough out onto a baking sheet coated with cooking spray; with lightly floured hands, shape the dough into a 10-inch-long roll; flatten the roll to a 1-inch thickness.
Bake the roll at 325 for 30 minutes.
Remove the roll from the baking sheet, and cool for 10 minutes on a wire rack.
Cut roll diagonally into 14 (1/2-inch) slices using a serrated knife.
Place the slices, upright, on baking sheet.
Bake the slices at 325 for 15 minutes (the cookies will be slightly soft in center but will harden as they cool).
Remove from baking sheet; cool completely on wire rack.
Note: Store in an airtight container. To freeze up to 6 months, place biscotti in an airtight container.
