Preheat your oven to 350°F (175°C) and prepare two 8-inch cake pans with nonstick spray and parchment paper.

Sift together the all-purpose flour, black cocoa powder, granulated sugar, baking powder, baking soda, and salt in a large mixing bowl.

In another bowl, whisk together buttermilk, canola oil, eggs, and vanilla extract until fully combined.

Make a well in the center of your dry ingredients and pour in the wet mixture. Fold until just combined, then stir in hot coffee.

Divide the batter between prepared cake pans and bake for 30-33 minutes, checking with a toothpick for doneness.

Allow the cakes to cool completely on wire racks.

In a saucepan over medium heat, combine fresh blackberries, granulated sugar, lemon juice, lemon zest, and the cinnamon stick.

Bring to a gentle boil and cook for 5-6 minutes, stirring occasionally before thickening with a cornstarch slurry. Remove from heat and let cool.

In a mixing bowl, beat the softened cream cheese and unsalted butter until creamy, then gradually sift in powdered sugar and black cocoa powder.

Level the cooled cakes and place one layer on a serving platter, spreading blackberry compote and frosting between layers before adding the second cake layer.

Apply a crumb coat of frosting and chill for about 30 minutes before the final frosting application.

Finish frosting the cake until smooth and decorate with chocolate skulls and rose petals.