Preheat the oven to 350°F (175°C). Grease and flour a skull cake pan.

In a large mixing bowl, whisk together the flour, sugar, cocoa powder, baking powder, baking soda, salt, and ground ginger.

In another bowl, mix the buttermilk, vegetable oil, eggs, and vanilla extract until well combined.

Gradually add the wet ingredients to the dry ingredients, mixing until just combined.

Pour the batter into the prepared skull cake pan and smooth the top.

Bake for 30-35 minutes or until a toothpick inserted into the center comes out clean.

Let the cake cool in the pan for 10 minutes, then transfer to a cooling rack to cool completely.

In a large mixing bowl, beat the softened butter until creamy.

Gradually add the powdered sugar and cocoa powder, mixing on low speed until combined.

Add the heavy cream and vanilla extract, then beat on high speed until the frosting is light and fluffy.

Once the cake is completely cool, spread a layer of frosting on top and around the sides of the cake.

Drizzle melted white chocolate over the top and sprinkle with black sprinkles for decoration.

Slice and serve the cake at your Halloween gathering.