Bake cupcakes according to directions (you will want to use the paper liners on your cupcakes). Cool fo few minutes before removing cupcakes, then place on cooling rack.
For filling, combine water and salt, until salt is dissolved; them let cool. In a small bowl, beat the marshmallow creme, shortening, sugar and vanilla until light and fluffy; add the salt mixture.
Take the creme filling and add to a pastry bag. For the pastry bag, you will want to use a round tip. Push thru the bottom of the paper liner to fill each cupcake.
For the Ganache, place chocolate in a small bowl. In a saucepan, bring cream just to a boil. Pour over chocolate; whisk until smooth. Cool, stirring occasionally, to room temperature or untuil ganache reaches a spreading consistency.
Dip cucakes tops into frosting, chill for about 20 minutes or until set. Store in refrigerator.