In a medium bowl sift the flour, baking powder and salt. Set aside.
In a large bowl on medium speed beat the butter and sugar until creamy approximately 3 minutes, then add the egg and vanilla and combine. Add the sifted flour mixture a little at a time until combined.
Place the dough on a lightly floured flat surface and gently form into a ball (do not over knead). Wrap the dough in plastic and refrigerate for one hour.
Pre-heat oven to 350F (180C). Line two cookie sheets with parchment paper.
Place the dough on a lightly floured flat surface and roll (you can use half the dough at a time) to a little thicker then 1/8 inch thick. Place on cookie sheets and bake for 10-12 minutes, or until edges or lightly golden. Let cool 5-8 minutes then move to cookie rack to cool completely, before serving. Dust with powdered sugar if desired. Enjoy!
The dough can also be formed into a log, wrapped in plastic and refrigerated. Then just slice and bake.