Heat oven to 350 degrees F. Line a large baking sheet with parchment paper.
Beat the butter and 1/4 cup confectioners' sugar until smooth. Beat in the vanilla and salt. Slowly add the flour and blend until fully incorporated. Mix in the pecans.
Roll dough into 1" balls and place on prepared baking sheet. Bake 15 minutes. Let cookies cool completely on baking sheet before removing (it is important to do this - the cookies are very fragile when warm!).
Place the remaining 1/4 cup confectioners' sugar in a small bowl and roll each cooled cookie in the sugar until evenly coated.