Heat oven to 375 degrees F. Spread almonds evenly on baking sheet. Toast almonds at 375 degrees F for 4 to 5 minutes or until lightly browned. Let cool. Coarsely chop.
Mix together flour, baking powder and salt in a small bowl. Beat together butter and sugar in medium-size bowl until creamy. Beat in egg, yolk, vanilla, rind and almond extract. Stir flour mixture into butter mixture to form dough. Stir in almonds.
Place dough on a baking sheet. Shape into 11 x 4-inch log. If too soft, refrigerate to firm.
Bake in 375 degree F oven for 15 to 18 minutes or until lightly browned. Remove log to cutting board. Let stand until cool enough to handle, about 10 minutes.
Reduce oven temperature to 325 degrees F.
Using serrated knife, cut log crosswise on a slight angle into 1/2-inch-thick slices. Carefully transfer to baking sheet, a cut side down.
Bake in 325 degree F oven for 15 to 20 minutes or until golden. With spatula, transfer biscotti to wire rack to cool.
Line baking sheet with waxed paper. Place chocolate in medium-sized metal bowl. Set over simmering water in saucepan. Stir chocolate occasionally until melted. Dip one end of biscotti in chocolate and place on waxed paper. Let stand in cool place until chocolate is firm.