Ingredients:

  • 2 cups all-purpose flour
  • 2 cups granulated sugar
  • 0.75 cup black cocoa powder
  • 2 tsp baking powder
  • 1.5 tsp baking soda
  • 1 tsp fine sea salt
  • 2 large eggs
  • 1 cup full-fat buttermilk
  • 0.5 cup neutral oil
  • 1 tbsp pure vanilla extract
  • 1 cup boiling water
  • 1.5 cups unsalted butter, softened
  • 4 cups powdered sugar
  • 0.5 cup black cocoa powder (for frosting)
  • 4 tbsp heavy cream
  • 1 pinch salt

Instructions:

  1. Prep the environment. Preheat your oven to 350°F (175°C). Grease two 8 inch round cake pans and line the bottoms with parchment paper. Note: Parchment is non negotiable for this high moisture batter.
  2. Sift the dry base. Sift together the 2 cups all purpose flour, 2 cups granulated sugar, 3/4 cup black cocoa powder, 2 teaspoons baking powder, 1.5 teaspoons baking soda, and 1 teaspoon of sea salt into a large mixing bowl. Whisk until the color is a uniform charcoal grey.
  3. Incorporate the wet elements. Make a well in the center of the dry ingredients and add the 2 large eggs, 1 cup buttermilk, 0.5 cup neutral oil, and 1 tablespoon vanilla extract. Whisk from the center outward until the batter is thick, glossy, and smooth.
  4. Perform the hot bloom. Carefully pour in the 1 cup boiling water and whisk gently. Note: This will look alarming as the batter turns very liquid, but it's correct. Whisk until no streaks of water remain and the batter is obsidian dark.
  5. Bake the layers. Divide the batter evenly between the prepared pans. Bake for 30 minutes until a toothpick inserted into the center comes out clean and the edges pull slightly away from the pan.
  6. Cool with patience. Allow the cakes to cool in the pans for 10 minutes. Then, transfer to a wire rack to cool completely for at least 1 hour. The cake must be cold to the touch before frosting.
  7. Cream the butter base. Prepare the obsidian buttercream by beating the 1.5 cups softened butter with a hand mixer or stand mixer until it looks pale and incredibly fluffy.
  8. Build the frosting color. Gradually add the 4 cups powdered sugar and 0.5 cup black cocoa powder. Stream in the 4 tablespoons heavy cream and a pinch of salt. Beat until the frosting is light, airy, and the color of coal.
  9. Assemble the masterpiece. Place one cake layer on a plate, spread a thick layer of frosting, and top with the second cake. Use the remaining buttercream to coat the top and sides.
  10. Final set. Let the frosted cake sit for 20 minutes before slicing until the frosting has slightly crusted.