Combine 1 1/2 cups powdered sugar with a couple of drops of vanilla or other flavoring and enough milk (2 to 3 Tbsp.) to make a firm, slightly runny icing. Color as desired. iced cookies can be decorated with fondettes, colored sprinkles, etc (available at The Specialty Shop) while the icing is still soft. Icing will set to give a firm, smooth, glaze finish.