Shake and Strain the Butterscotch, Bailey's, and Goldschlager into a cocktail glass. Float the Sambuca, then sprinkle Cinnamon or Nutmeg into drink (Before you flame the drink). Just before presentation, flame the drink. As the Sambuca burns, the cinnamon will sparkle. A dazzling effect if the bartender or server is walking with the drink while it's burning (give the comet a tail).
More info on how to make a Bailey's Comet