Preheat oven to 325°. Cream butter and sugar until light and fluffy. Gradually beat in flour. Press dough into an ungreased 9-in. square baking pan. Prick with a fork.

Bake until light brown, 30-35 minutes. Cut into squares while warm. Cool completely on a wire rack. If desired, dust with confectioners' sugar. Yield: 16 cookies.