Instructions

CUPCAKES

1. Adjust an oven rack to the center position and heat oven to 350 degrees. Line 2 cupcake pans with cupcake liners and set aside.
2. In a large bowl, whisk the flour, baking soda, baking powder, and salt together.  In a separate bowl, combine the chopped chocolate, instant espresso powder or coffee powder, and boiling water and whisk until the chocolate is melted and combined.
3. In the bowl of a stand mixer fitted with the paddle attachment, beat together the butter and sugar on medium-high speed until fluffy and pale in color, about 3 minutes. On low speed add eggs one at a time mixing until just combined. Add in the sour cream and vanilla extract and mix on low until incorporated. Add flour in 3 additions, alternating with the chocolate mixture in 2 additions.  Scrape down the sides of the bowl needed and give the batter a final stir by hand with a rubber spatula.
4. Divide the batter into the prepared cupcakes pans, filling about 2/3 full. Gently even out the batter but tapping gently on the counter and bake until a toothpick inserted in the centers comes out with a few moist crumbs attached, about 12 to 15 minutes, rotating pans halfway through baking. Let cupcakes cool in their pan for 10 minutes on a cooling rack, then invert on cooling rack to cool completely.

FROSTING

1. In the bowl of a stand mixer, whisk together the sugar, egg whites, cold water, corn syrup, cream of tartar and salt. Fill a saucepan with about 1 inch if barely simmering water and set bowl on top, making sure the bottom of the bowl does not touch the water. Attach a candy thermometer to the bowl and constantly whisk mixture until it reaches 160 degrees, about 10 minutes.
2. Remove thebowl from the heat and transfer to a stand mixer fitted with the whisk attachment. Whip the egg white mixture on medium speed until soft peaks form, about 5 minutes. Add vanilla extract and continue to whip until the mixture has cooled and stiff peaks form, about 7 minutes. Frosting must be used immediately.

ASSEMBLE

1. Fit a piping tip #808 in a piping bag. Fill bag with frosting. Pipe swirls on each cupcake. Carefully place ghost face pieces on each cupcake, using a toothpick or wooden coffee stir to press and adhere to the frosting. Serve immediately.