In mixer bowl on low speed, blend butter until creamy; add egg & dry gingerbread mix, adding 1 tbs of water at a time until a moist dough forms & dough pulls away from side of bowl. Form dough into a disk and wrap in plastic. Refrigerate 1-2 hours.
Preheat oven to 350˚F. Line cookie sheet with parchment paper, if desired. Roll dough 1/4" thick on well floured surface. Cut with gingerbread man cutter. Use a knife to make dash marks on the cookies.
Bake 13-15 minutes. Cool on pan. Prepare frosting by mixing all ingredients together. Fill the piping bag with the prepared frosting. Flip the cooked gingerbread man cookie upside down and pipe to decorate. Add jelly beans, gummy bears, and other candies.