Preheat oven to 375°F (190°C). Line baking sheets with parchment paper.
In a large bowl, cream together butter and 0.5 cup powdered sugar until light and fluffy. Beat in vanilla extract.
In a separate bowl, whisk together flour and salt. Gradually add to the butter mixture, mixing until just combined. Stir in pecans.
Roll dough into 1-inch balls and place on prepared baking sheets.
Bake for 10-12 minutes, or until bottoms are lightly golden. Let cool on baking sheets for a few minutes before rolling in powdered sugar. Roll again in powdered sugar once cooled completely.
Notes
For best results, use high-quality butter and fresh pecans. Store cookies in an airtight container at room temperature.