Cake-Shaping Strip (from 8 sushi-mat segments)
Heavy-duty aluminum foil
Prepared cake batter (see the Almond Cake batter or prepare batter using about 1 box of cake mix)
Fondant (see the Easy Marshmallow Creme Fondant recipe)
1 (16-oz.) container of store-bought white frosting
Black piping gel
1. Line a sheet pan with two sheets of aluminum foil. Shape the Cake-Shaping Strip into a shape of a ghost. Exaggerate the spatial features, as they'll seem smaller after you unwrap and ice the cake. Wrap the bottom foil layers around the strip. Cut the foil or add extra bottom foil strips as needed to wrap around the strip. Press small balls of loosely packed foil into outer corners or edges if you think that the foil didn't wrap around the portion well enough to prevent cake-batter leakage.
2. Prepare your cake batter. Spray the strip and foil with cooking spray. Pour the cake batter into the prepared "pan" and bake until done. Let the cake cool.
3. Cut away any cake batter that leaked through the strip. Carefully remove the Cake-Shaping Strip. Insert the flat edge of a table knife between the strip and the cake if this helps.
4. Generously spray two pieces of vinyl mats with cooking spray. Place the fondant between the mats and roll it out. Apply a medium-thick layer of the store-bought frosting to the head portion of the cake. Gently remove the top mat, and flip the bottom mat (with the rolled out fondant) on the cake. Gently press fondant into the cake, and cut away the excess.
5. Pipe on ghost facial features with black icing. Alternatively, cut out holes in the fondant and fill the holes with melted chocolate (made by microwaving 1/4 cup dark chocolate and 1 teaspoon canola oil until smooth).