Step 1: Bake the Chocolate Cake Layers

1. Preheat your oven to 350°F (175°C). Grease and line your cake pans with parchment paper.
2. In a large bowl, whisk together flour, sugar, cocoa powder, baking soda, baking powder, and salt.
3. Add buttermilk, oil, eggs, and vanilla. Beat on medium speed for 2 minutes until well combined.
4. Carefully pour in the hot coffee and mix on low until the batter is smooth. The batter will be thin – this is normal and ensures a moist cake.
5. Divide batter evenly between the pans and bake for 30-35 minutes, or until a toothpick inserted in the center comes out clean.
6. Let cakes cool in pans for 10 minutes, then turn out onto a wire rack to cool completely.

Step 2: Make the Vanilla Buttercream

1. In a large bowl, beat the softened butter on high speed for 3-4 minutes until pale and fluffy.
2. Gradually add 5 cups of powdered sugar, mixing on low. Add heavy cream, vanilla, and salt.
3. Beat on high for 2-3 minutes until light and creamy. If too thin, add more sugar; if too thick, add a splash more cream.
4. Reserve 1/2 cup of white buttercream for the web if you are not using white chocolate.

Step 3: Assemble and Frost the Cake

1. If needed, level the cake layers with a serrated knife for a flat top.
2. Place one cake layer on your serving plate. Spread a generous layer of white buttercream on top.
3. Add the second layer and apply a thin crumb coat (a light layer of frosting all over the cake). Chill for 15-20 minutes.
4. Once chilled, tint the remaining buttercream with black gel food coloring. Add a little at a time until you reach a deep black. Frost the entire cake smoothly with the black buttercream using an offset spatula.
5. Chill the frosted cake for another 15 minutes to set the base.

Step 4: Create the Signature Spiderweb

1. Melt white chocolate chips in 20-second intervals in the microwave, stirring until smooth. Let it cool slightly, then transfer to a piping bag. (Or use your reserved white buttercream).
2. Starting from the center of the cake, pipe a small dot, then pipe 3-4 concentric circles around it, spacing them about 1.5 inches apart.
3. Immediately take a toothpick and drag it from the center dot straight out to the edge of the cake. Wipe the toothpick clean.
4. Repeat, dragging lines from the center outward every 2-3 inches around the cake to create the web effect. For a more authentic web, alternate dragging lines from the edge inward toward the center.
5. Add plastic spiders or pipe a small spider with leftover black frosting for the final creepy touch.