Coat a cookie sheet with nonstick cooking spray; set aside.
In a small bowl, stir together flour, baking powder, and salt. In a large mixing bowl, beat butter, sugar, egg yolk, and orange flavoring with electric mixer on medium-high speed until smooth. Add flour mixture and orange peel; beat on low speed just until combined.
Using a cookie press fitted with a star disk or ribbon disk, force unchilled dough into 2-1/2-inch sticks or ribbons 1/2 inch apart on prepared cookie sheet. (Or use pastry bag fitted with a star tip.)
Bake in a 350 degree F oven for 8 to 10 minutes or until edges are firm, but not brown. Transfer to a wire rack; cool.
In a small saucepan, melt chocolate and shortening together. Place nuts in a small, shallow bowl. Dip about 1 inch of the end of each cookie into chocolate; dip coated tip into the nuts. Place dipped cookies on waxed paper to set. Store in a covered container in your refrigerator for up to 2 weeks. Makes about 60 cookies.