• Preheat oven to 350°F. Line 12 to 14 muffins cups with paper liners. You may be able to get up to 14 depending on the size of your muffin cups, but start with 12.
• In a mixing bowl, combine the chocolate and cocoa powder. Pour the hot coffee over chocolate and stir until melted and smooth.
• Whisk the oil into the chocolate mixture, then whisk in the eggs, vanilla and vinegar.
• Mix together the flour, sugar, baking soda and salt, then add to the bowl and beat with a scraper until you have a smooth and shiny batter.
• Divide batter evenly between the cups filling about ⅔ cup full,
• Bake for 18 to 20 minutes or until cakes spring back when lightly touched. Let them cool completely while you prepare the filling.

Marshmallow Creme Vanilla Filling

• Put 3 tablespoons of water in a large microwave-safe bowl. Sprinkle ¾ teaspoon of plain gelatin over the water and let sit for 5 minutes. Microwave the bowl for 20 to 30 seconds to heat the water, then stir to dissolve gelatin. Whisk in the softened butter, vanilla and salt until smooth. Let cool until just warm to touch, then whisk in 1 ¼ cups marshmallow creme.
• Put the bowl in the refrigerator for 30 minutes to set.
• Transfer about ⅓ of the marshmallow mixture to a pastry bag fitted with a writing tip.

Assembling

• To fill the cupcakes, insert the tip of a paring knife at a 45 degree angleabout ¼ inch from the edge of the cupcake and carve out a little cone. Spoon a tablespoon of the filling into the cavity. Cut off all but about a quarter inch of the cone and use the remaining piece to cover the filling. After assembling the cupcakes, put them on a tray in the refrigerator to help set the filling more.

Make the Glaze

• Put 3 tablespoons of softened butter in a microwave-safe bowl. Add ½ cup semisweet chips and stir to coat chips. Heat on high for 30 seconds. Stir well. Repeat, melting and stirring until mixture is shiny. Let sit for about 10 minutes to thicken slightly.
• Spoon about 2 teaspoons of chocolate glaze over the cupcakes and let set. Once set, pipe the swirls of reserved marshmallow mixture over the top.