Preheat oven to 375 degrees F. Cut cookie dough into 15 equal pieces. Divide each dough piece into graduated-size balls: about 1 inch, 3/4 inch, and 1/2 inch in diameter. On an ungreased large cookie sheet, arrange each set of balls into a snowman shape, placing balls 1/4 inch apart and snowmen at least 3 inches apart.
Bake for 10 to 12 minutes or until edges are lightly browned. Cool on cookie sheet for 3 minutes. Transfer cookies to a wire rack and let cool.
Spread cooled cookies with Royal Icing. Decorate as desired with chocolate pieces and/or candies.
In a mixing bowl, combine meringue powder and warm water. Add powdered sugar, vanilla, and cream of tartar. Beat with an electric mixer on low speed until combined; beat on high speed for 7 to 10 minutes or until very stiff. When not using icing, keep it covered with plastic wrap. If necessary, thin icing with a little water.