01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - Whisk together flour and salt in a medium bowl until thoroughly blended.
03 - Beat butter and granulated sugar in a large bowl until light and fluffy, approximately 3 minutes.
04 - Mix in egg yolk and vanilla extract until fully incorporated into the butter mixture.
05 - Gradually add flour mixture to wet ingredients, mixing just until dough forms. Do not overmix.
06 - Roll tablespoon-sized portions of dough into balls. Place 2 inches apart on prepared baking sheets.
07 - Gently press each dough ball with fork tines or glass bottom to slightly flatten.
08 - Bake for 10-12 minutes until edges are just turning golden. Remove promptly to prevent overbaking.
09 - Let cookies rest on baking sheet for 5 minutes, then transfer to wire rack to cool completely.
10 - Lightly dust cooled cookies with powdered sugar if desired.