In an electric mixer beat the room temperature butter and quarter cup powdered sugar until well mixed. Beat in the lemon peel and vanilla extract. Add flour and salt mixing until just combined. Make a disk out of the dough, wrap in plastic paper and refrigerate for 20 to 30 minutes. Before cutting cookies allow dough to sit for about 5 minutes to prepare dough for rolling. On a floured (or powdered sugar) surface, roll out the disk of dough to about 1/4 inch thickness; do not over work. Cut out your cookies. Place cookies on baking sheet and bake at 350 degrees. Bake about 15 minutes until light brown on bottom and just a little brown on the edges - you don't want them over cooked. Transfer your cookies to a baking rack and allow to cool completely. Dust with powdered sugar or with lemon glaze.