Halloween Cake

Directions

1. Preheat your oven to 200°F. Prepare a baking sheet by lining it with parchment paper. In the bowl of a stand mixer fitted with the whisk attachment, place the egg whites. Whisk them for 30 seconds until small bubbles form. Add the salt and cream of tartar, then whisk on medium speed for 1 minute until a fine foam appears. With the mixer running, slowly stream in the sugar, allowing each addition to be absorbed before adding more. Once all sugar is added, continue whisking on medium for 8 minutes until soft peaks form. Add the vanilla and whisk another 3 minutes until stiff peaks hold.
2. Carefully transfer the meringue to a piping bag fitted with a round tip. Pipe ghost shapes onto the prepared baking sheet by holding the bag at a 90° angle. Apply steady pressure until the base reaches the desired width, then slowly lift the bag while continuing to apply pressure until you reach a suitable height. Finally, gently release the pressure and quickly pull the bag upward to create a small curl for the ghost's head.
3. Place the baking sheet into the oven on the center rack and bake for 2½ hours. After baking, turn the oven off and leave the meringues inside with the door closed for 3 hours to let them dry completely. Once dried, use a toothpick dipped in black food coloring to add small dot eyes to each ghost.
4. Now preheat your oven to 350°F. Line the bottoms of three 9-inch cake pans with parchment paper and lightly spray with baking spray. In a medium bowl, combine the flour, cocoa powder, baking soda, salt, and baking powder. In the stand mixer fitted with the paddle attachment, cream together the white sugar, brown sugar, butter, and vegetable oil on medium speed for 2 minutes until smooth. Add the eggs, milk, sour cream, and vanilla, and mix until combined.
5. With the mixer running on low, add black food coloring a few drops at a time until the batter reaches your desired darkness. Then add the flour mixture and mix just until combined. Pour in the hot coffee and mix to incorporate. Evenly divide the batter among the three prepared pans. Bake on the center rack for 25 minutes, or until a toothpick inserted in the center comes out clean or with a few moist crumbs. Remove from the oven and let the cakes cool completely on a wire rack before frosting.
6. For the frosting, use the stand mixer with the paddle attachment to combine the powdered sugar, butter, milk, vanilla, and salt. Beat on medium-high speed until smooth and creamy. Divide the frosting equally between two bowls. Add purple food coloring to one bowl and mix until you achieve the desired hue. Stir black food coloring into the other bowl until it's as dark as you like.
7. Once the cakes are completely cool, remove them from the pans. Place the first cake layer on a serving plate or cake stand and spread half of the purple frosting over the top. Position the second cake layer on top and frost it with the remaining purple frosting. Finally, place the third layer on top.
8. Now, coat the entire outside of the cake—top and sides—with the black frosting, using an icing spatula to achieve a smooth finish. Decorate the frosted cake by placing the ghost meringues on top. Slice into 8 to 10 pieces and serve.
9. Any leftover cake can be stored in an airtight container at room temperature for up to 3 days.