01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - Whisk together flour and salt in a medium bowl until well 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.
05 - Gradually add flour mixture to wet ingredients, mixing just until dough comes together. Do not overmix.
06 - Roll tablespoonfuls of dough into balls. Place 2 inches apart on prepared baking sheets.
07 - Gently press each ball with fork tines or bottom of glass to flatten slightly.
08 - Bake for 10-12 minutes until edges just begin turning golden. Avoid overbaking.
09 - Let cool on baking sheet for 5 minutes, then transfer to wire rack. Dust with powdered sugar if desired once completely cooled.