In large bowl, beat butter, brown sugar, molasses and cold water with electric mixer on medium speed (or with wooden spoon) until well mixed. Mixture may look curdled. With wooden spoon, stir in remaining cookie ingredients until soft dough forms. Wrap with plastic wrap; refrigerate until firm, at least 2 hours.
Heat oven to 350°F. Lightly spray cookie sheets with cooking spray. On floured surface, roll dough 1/8 inch thick.
Cut dough with floured 3 1/2- by 2 1/2-inch gingerbread boy or girl cookie cutter or other cookie cutter. Place on cookie sheets 2 inches apart. Reroll dough, and cut additional cookies.
Bake 10 to 12 minutes or until no indentation remains when touched. Immediately remove from cookie sheets to cooling rack. Cool cookie sheets 10 minutes between batches. Cool cookies completely, about 30 minutes.
In medium bowl, beat meringue powder and cold water with electric mixer on medium speed until peaks form. Gradually beat in powdered sugar until soft peaks form, about 1 minute. Spoon icing into decorating bag fitted with medium round tip, and pipe over cookies. Sprinkle with sugar. Let stand about 5 minutes or until icing is set.