Yields 18-24 cupcakes
1 3/4 cups all-purpose flour
1 1/2 cups granulated sugar
3/4 cup cocoa powder
2 teaspoons baking soda
1 teaspoon baking powder
Pinch of salt
1 cup strong black coffee (or 1 heaping tablespoon espresso powder dissolved in 1 cup water)
1 cup buttermilk
1/2 cup vegetable oil
1 tablespoon vanilla extract
Preheat oven to 350 degrees F (175 degrees C). Line cupcake tin with baking cups.
In a large bowl, whisk together the flour, sugar, cocoa powder, baking soda, baking powder, and salt. Add the eggs, coffee, buttermilk, vegetable oil, and vanilla extract and beat for 2-3 minutes on medium speed to mix. Batter will be liquidy.
Fill baking cups 2/3 of the way full and bake for 15-18 minutes, or until a toothpick inserted into the cake comes out clean with a few crumbs. Cool cupcakes to room temperature before filling and frosting.
Toasted Marshmallow Filling
8 large white marshmallows
1/2 cup Marshmallow Fluff (or prepared marshmallow cream)
1/2 cup vegetable shortening
1/2 cup confectioners sugar
2 teaspoons vanilla extract
Turn oven on to broil. Place marshmallows 1-inch apart on a non-stick baking mat (such as a Silpat) or a parchment-covered baking sheet. Heat under broiler until lightly browned. Watch very closely! The marshmallows will brown very quickly.
In a medium bowl, beat together the toasted marshmallows, marshmallow fluff, shortening, sugar, and vanilla extract until light and fluffy, about 3-5 minutes.
Malted Chocolate Buttercream
1/2 lb butter (2 sticks or 1 cup) at room temperature
1 cup powdered sugar
1 teaspoon pure vanilla extract
1/3 cup malt powder
1 cup (6 ounces) semi-sweet chocolate, melted
1/4 cup heavy whipping cream
In a large bowl, beat together butter and powdered sugar until light and fluffy, about 1 minute. Add vanilla and malt powder and mix on low speed until just combined. Add melted chocolate and whipping cream. Beat on high until well combined, about 2 minutes. Best if used immediately, but keeps well at room temperature.
Using a sharp knife (or cupcake corer), cut out a cavity in the center of the cupcake. I run the knife in a circular motion, while always pointing the knife towards the center of the cupcake. The cavity should be coned shaped. Using a pastry bag, fill the cupcake with the toasted marshmallow filling until the marshmallow just reaches the top.
Pipe the malted chocolate buttercream frosting on top of the cupcake. Garnish with chocolate sprinkles and whoppers.