Prepare brownie mix as directed on the package. Pour into a 9x13 greased pan and bake as directed.
Once the brownies are ready, let them cool completely to room temperature. Cut cooled brownies using star cookie cutter. Lay cut brownies out on a parchment lined cookie sheet.
Prepare Icing:
Mix butter with electric mixer until it's creamy. Once creamy, add salt, vanilla powdered sugar and milk. Blend until well combine and has desired consistency. Should be thick.
Put Together:
Put icing into piping bag with desired decorating tip or in a sandwich zip bag and cut a corner off. Pipe icing onto one star brownie then place another brownie on top to form a sandwich. Place sprinkles along the edges of white icing. Enjoy.