Preheat the oven to 350˚F. Line a baking sheet with parchment paper.
In a large bowl, beat together the butter and the ½ cup of icing sugar, and beat together until smooth and creamy. Add in the vanilla extract until fully incorporated.
Add in the flour and pecans, and mix until just combined.
Roll about 1 tablespoon of dough into balls, and place on the prepared baking sheets.
Bake in the preheated oven for around 15 minutes.
Sift ⅓ cup of sugar into a medium bowl. While the cookies are still warm, roll in icing sugar. Let the cookies cool completely on wire racks, then roll in icing sugar again.