Last Updated: January 4, 2011 at 4:40 am
Whisk together the flour, baking powder, and salt in a large bowl. Beat butter and sugar with a mixer on medium-high speed until fluffy. Beat in egg and vanilla. Reduce speed to low, and add the flour mixture gradually, and beat until combined. Shape the dough into two disks, wrap each one with plastic wrap, and refrigerate until firm, about 1 hour.