Cream the butter and sugar in a mixing bowl. Beat in the egg, then add the flour, vanilla and salt. Mix well. Chill the dough 3 to 4 hours before rolling. Preheat the oven to 350 degrees. Roll out and cut with a 2-inch cookie cutter. Bake for 8 to 10 minutes or until lightly colored. Cool completely before frosting.
Makes about 50 cookies