Cream 1/2 cup of butter or margarine. Add brown sugar and beat. Beat in egg and molasses. In a separate bowl, combine 2 3/4 cups of flour, soda and spices. Add to butter mixture. Blend well.
Roll dough out 1/8 inch thick on floured surface. Cut into shapes. Bake for 6-8 minutes.
To Make Frosting: Cream 1/3 cup butter. Gradually add 2 cups sifted confectioners sugar, 1 tablespoon milk and 1/2 teaspoon vanilla. Beat until smooth. Put in a pastry bag with small tip and decorate cookies.