1. Heat oven to 350 degrees F. Lightly coat baking sheet with nonstick vegetable-oil cooking spray.
2. Combine flour, baking powder and salt in a small bowl. Beat together butter, sugar and egg yolk in bowl until smooth. At low speed, beat in the flour mixture and orange rind just until combined.
3. Spoon dough into spritz gun fitted with star disk. Pipe 2-1/2-inch-long sticks onto prepared sheets, spacing 1/2 inch apart.
4. Bake in 350 degree oven for 8 to 10 minutes or just until lightly golden. With spatula, transfer cookies to wire rack to cool.
5. Melt together chocolate and vegetable shortening in a small saucepan. Place the nuts in a small shallow bowl. Dip about 1 inch of the end of each cookie into chocolate; dip chocolate-coated tip into the nuts. Place on waxed paper to cool completely. Store airtight, refrigerated, for up to 3 weeks. Makes about 7 dozen cookies.