In a large bowl, cream butter, brown sugar and egg. Mix until well blended.
Slowly add flour and salt and mix well. Cover and refrigerate for at least one hour.
Preheat oven to 375 degrees F.
Roll one inch pieces of dough into balls and place 2 inches apart on cookie sheets. Flatten balls with the bottom of a glass dipped in flour. Press a pecan into top of dough.
