Preheat the oven to 350°F (175°C) and prepare two 9-inch cake pans by greasing and flouring them.
Sift together the flour, sugar, baking soda, salt, and cocoa powder in a large mixing bowl.
In a separate bowl, gently whisk the vegetable oil, buttermilk, eggs, black food coloring, vanilla extract, and vinegar until combined.
Slowly combine the wet ingredients into the dry ingredients, stirring just until everything is mixed.
Add the hot coffee to the batter and stir until smooth.
Divide the batter evenly between the two prepared pans.
Bake for 30 to 35 minutes, or until a toothpick inserted into the center comes out clean.
Cool the cakes in the pans on a wire rack. Once cool, remove them from the pans.
Layer the cakes with blackberry preserves in between and on top. Garnish with fresh blackberries and sprinkle edible glitter.