In a large bowl, cream butter and sugar until light and fluffy. Beat in egg. Combine the flour, baking soda and spices. Combine the molasses, orange juice and zest. Add dry ingredients to the creamed mixture alternately with the molasses mixture, beating well after each addition.
Drop by tablespoonfuls 2 in. apart onto greased baking sheets. Bake at 375° for 10-12 minutes or until edges are set. Remove to wire racks to cool completely.
For glaze, combine confectioners' sugar and enough orange juice to achieve desired consistency. Spread over cooled cookies.