Anything baked by my friend the food writer Melissa Clark is outstanding, but shortbread is her particular forte. Admiring the intriguingly flavored crumbly cookies she so effortlessly whips up for parties, I asked her to devise shortbread with a Spanish theme. Her response was this recipe, so delicious and easy I now bake these practically every week. The shortbread is a perfect match for Sauternes, accentuat