• Preheat oven to 375 degrees F.
• Line a muffin pan with themed cupcake liners.
• In a large bowl, sift together the flour, baking powder, baking soda, cocoa and salt. Set aside.
• In a large bowl, cream together the butter and sugar until light and fluffy, about two minutes.
• Add the eggs one at a time, beating well with each addition, then stir in the vanilla.
• Add the flour mixture alternately with the milk; beat well.
• Fill the muffin cups 3/4 full.
• Bake for 15 to 18 minutes, until a toothpick inserted into the cake comes out clean.

For the frosting and decoration:

• Place softened butter into a bowl, and beat in two cups of icing sugar.
• Add two Tablespoons heavy cream and vanilla.
• Add remaining icing sugar 1/2 cup at a time until you reach your desired consistency.
• Add food coloring, if using.
• Spoon the frosting into a piping bag with no tip or a circular tip.
• Swirl the frosting onto the cooled cupcakes.
• Melt the candy melts with the shortening for 25 seconds, stir, and reheat if necessary.
• Place a large marshmallow in the center of each cupcake, and spoon one to two Tablespoons of the candy melts over the top.
• Use the back of a spoon to help the candy melts move if needed.
• Repeat with the other ghost cupcakes.
• After each ghost has dried for about five minutes, attempt to attach the eyes – if the candy melts are still too soft, give it another couple minutes before re-attempting.