01 -
Preheat oven to 350°F. Line two 8-inch cake pans with parchment paper and grease with cooking spray. In a large bowl, whisk together all-purpose flour, cocoa powder, baking soda, and kosher salt.
02 -
In a separate large bowl, whisk hot coffee with granulated and brown sugars until dissolved. Add vegetable oil and sour cream; whisk to combine.
03 -
Pour wet ingredients into dry ingredients and whisk until just combined. Divide batter evenly between prepared pans. Bake 25 to 30 minutes or until a toothpick inserted in the center comes out clean. Let cool 15 minutes in pans, then invert onto wire racks to cool completely.
04 -
Preheat oven to 225°F. Line a large baking sheet with parchment paper. Combine granulated and powdered sugar in a small bowl. Using a hand or stand mixer fitted with a whisk attachment, beat egg whites and cream of tartar on low speed until mostly combined. Increase speed to medium until whites become frothy.
05 -
Slowly add combined sugars a little at a time while continuing to beat. Increase speed to high and beat until medium peaks form. Add vanilla extract gradually and continue beating until stiff peaks form. Transfer meringue to a piping bag fitted with a large round tip.
06 -
Pipe large, then progressively smaller circles on the baking sheet to form ghost shapes. Bake for 1 hour and 20 minutes until exteriors are firm. Allow to cool completely.
07 -
Wrap cooled cake layers in plastic wrap and freeze for 20 minutes. Beat softened butter until smooth. Gradually add powdered sugar and pinch of salt, beating until smooth and free of lumps. Add heavy cream and vanilla extract, beating until combined. Adjust consistency with additional heavy cream, 1 tablespoon at a time, until spreadable but stable. Reserve 1/4 cup frosting for decorating.
08 -
Unwrap and level cake tops with a serrated knife if needed. Place one layer on serving platter, spread half the frosting evenly on top. Add second layer and cover cake with remaining frosting on top and sides. Use bench scraper to smooth surfaces.
09 -
Tint reserved buttercream black with food coloring. Transfer to a pastry bag with a small round tip and pipe eyes and mouths onto cooled meringues.
10 -
Heat heavy cream in a small saucepan over medium heat until bubbles form around edges. Place chocolate chips in a heatproof bowl and pour hot cream over them. Let sit for 1 minute, then whisk until smooth and fully combined.
11 -
Pour about half of the ganache over the top of the cake. Use an offset spatula to smooth and encourage chocolate drips along the edges. Add more ganache as desired. Arrange decorated ghost meringues on top to finish.