Orange Shortbread

Directions

1. 1
   Preheat oven to 375F.
2. 2
   Blend together butter, superfine sugar, zest, and salt in a bowl with a fork.
3. 3
   Sift flour into butter mixture and blend with fork until mixture forms a soft dough.
4. 4
   Transfer dough to an ungreased large baking sheet and pat into a 10- by 5-inch rectangle.
5. 5
   Prick dough all over with fork and sprinkle with coarse sugar (if using), pressing it gently into dough with your fingertips to adhere.
6. 6
   Score dough crosswise with back of a knife into 6 rectangles (do not cut all the way through), then score each rectangle into 2 triangles.
7. 7
   Bake shortbread in middle of oven until edges are golden but center is pale, 12 to 17 minutes.
8. 8
   Cool on baking sheet on a rack 10 minutes, then cut into 12 triangles along scored lines while still warm.
9. 9
   Transfer triangles with a long spatula to a rack to cool completely.