Preheat oven to 375 degrees F. Line 2 large baking sheets with parchment paper (optional).
Using an electric mixer, cream together the butter, 1/2 cup powdered sugar, and vanilla until light and fluffy.
Blend in flour and salt until just combined. Stir in chopped nuts.
Roll dough into 1-inch balls. Place on parchment-lined baking sheets.
Bake 7-8 minutes, until bottoms are slightly browned.
Remove from oven and allow to rest 1-2 minutes until cool enough to handle.
Roll balls into powdered sugar then place on a sheet of waxed paper to cool.
When cool, roll balls into powdered sugar a second time.