Step 1: In a large bowl, cream together the softened unsalted butter and powdered sugar until light and fluffy. If using, mix in the vanilla extract.
Step 2: In a separate bowl, whisk together the all-purpose flour and salt.
Step 3: Gradually add the dry ingredients to the wet ingredients, mixing on low speed or by hand until just combined and a soft dough forms. Be careful not to overmix.
Step 4: Divide the dough in half. On a lightly floured surface, roll each half to about 1/4-inch thickness. Cut into desired shapes (rounds, rectangles, or fingers) using a cookie cutter or knife. Prick the tops of the cookies with a fork. Alternatively, you can form the dough into a log, chill, and then slice.
Step 5: Place the cut-out cookies onto a baking sheet lined with parchment paper. Chill the cookies in the refrigerator for at least 30 minutes (or up to 2 hours) before baking. Preheat your oven to 325°F (160°C).
Step 6: Bake for 20-25 minutes, or until the edges are lightly golden and the centers are still pale. The exact time will depend on your oven and cookie thickness.
Step 7: Remove from the oven and let the cookies cool on the baking sheet for 5-10 minutes before transferring them to a wire rack to cool completely. Enjoy!