Vanilla Bean Thins

Directions

1. 1
   Scrape vanilla seeds from pod with tip of a knife into confectioners sugar.
2. 2
   Halve pods crosswise and bury in sugar.
3. 3
   Cover tightly and let stand at least 24 hours and up to 1 month.
4. 4
   Discard pods and transfer vanilla sugar to a food processor.
5. 5
   Add flour, salt, and baking powder and pulse to combine.
6. 6
   Add butter and pulse just until mixture is in pea-size lumps.
7. 7
   Add yolk and pulse just until a dough forms.
8. 8
   Gather dough into 2 balls, then flatten into 2 (5-inch) disks and chill, each disk wrapped well in plastic wrap, until firm, at least 1 hour.
9. 9
   Preheat oven to 325F.
10. 10
    Roll out 1 disk (keep the other chilled) to less than 1/8 inch thick on a lightly floured surface with a floured rolling pin.
11. 11
    Cut out shapes with floured cookie cutter and chill scraps.
12. 12
    Arrange cookies 1/2 inch apart on a buttered large baking sheet.
13. 13
    Make more cookies with remaining dough, rerolling scraps (but only once).
14. 14
    Bake cookies in batches in middle of oven until edges are pale golden, 10 to 15 minutes.
15. 15
    Transfer to a rack to cool.