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

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

In another bowl, cream the butter and sugar until light and fluffy. Add the eggs one at a time, mixing well after each addition.

Mix in the buttermilk, grated ginger, and vanilla extract.

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

Pour the batter into the prepared 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 before transferring to a cooling rack.

In a saucepan, heat the heavy cream until just simmering. Remove from heat and add the chopped chocolate and grated ginger.

Let sit for a few minutes, then stir until smooth and glossy.

Allow the ganache to cool slightly before pouring over the cooled cake.

Once the ganache has set, decorate the cake with chocolate shavings and candy eyes to create a spooky effect.