In a large bowl, cream the butter and brown sugar until smooth. Stir in the vanilla extract.
Gradually mix in the flour until fully combined. Fold in the chopped pecans.
Shape the dough into a log on parchment paper. Wrap tightly and refrigerate for at least 1 hour.
Preheat oven to 350°F. Line a baking sheet with parchment paper.
Slice the chilled dough into ½-inch rounds. Arrange on the baking sheet.
Bake for 15 minutes or until the edges are lightly golden.
Remove from the oven and transfer cookies to a wire rack to cool completely.