Preheat your oven to 350°F (175°C). Grease and line two 8-inch round cake pans with parchment paper.

In a large mixing bowl, whisk together the flour, sugar, baking powder, and black cocoa powder.

Add the buttermilk, softened butter, eggs, vanilla extract, and black food coloring to the dry ingredients. Mix until well combined.

Gradually add the hot water to the batter, mixing until smooth. The batter will be thin.

Divide the batter evenly between the prepared cake pans.

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

Allow the cakes to cool in the pans for 10 minutes, then transfer to wire racks to cool completely.

While the cakes cool, prepare the blackberry compote. In a saucepan over medium heat, combine the blackberries, sugar, lemon juice, and cornstarch. Cook, stirring frequently, until the mixture thickens and the berries break down. Remove from heat and let cool.

For the frosting, beat the softened cream cheese and butter together until light and fluffy.

Gradually add the powdered sugar, black cocoa powder, salt, and vanilla extract. Continue to beat until smooth and creamy.

In a separate saucepan, heat the heavy cream until it begins to simmer. Pour over the chopped dark chocolate and let sit for 2 minutes. Stir until smooth and glossy to create the ganache.

Once the cakes are completely cool, place one layer on a serving plate. Spread a layer of blackberry compote over the top.

Place the second cake layer on top and frost the entire cake with the blackberry buttercream.

Drizzle the dark chocolate ganache over the top of the cake, allowing it to drip down the sides.

Decorate with fresh blackberries, edible gold leaf or glitter, and any other desired decorations.

Allow the cake to set for at least 30 minutes before slicing and serving.