Line a baking sheet with parchment or a silicone mat, and preheat oven to 400 degrees F.

In a small mixing bowl, whisk together flour and salt. Set aside.

In a medium-size mixing bowl, combine butter, ½ cup powdered sugar, and vanilla, and beat 3 minutes, until fluffy. Gently fold in flour and salt mixture along with the pecans, if using. The dough will be dry and crumbly.

Roll into 1-inch balls, and place on prepared baking sheet, keeping them about 1 inch apart.

Bake at 400 degrees for 10-12 minutes. Watch closely because you want them dry but not browned.

Immediately roll hot cookies in powdered sugar, and place on cooling rack to cool. When completely cool, roll in powdered sugar again.

Store in air-tight container.