Cream butter; gradually add sugar, beating at medium speed of an electric mixer until light and fluffy.
Add egg, vanilla, and salt, beating well.
Stir in flour.
Cover and chill 30 minutes.
Shape dough into two 8-inch logs, roll each log in chopped pecans.
Wrap logs in waxed paper; chill at least 2 hours.
Cut dough into 1/4-inch slices, place on ungreased cookie sheets.
Bake at 350Â° for 10 to 12 minutes or until lightly browned.
Cool cookies on wire racks.