Ingredients:

  • 2 cups (250 g) All-purpose flour, sifted
  • 2 cups (400 g) Granulated sugar
  • ¾ cup (75 g) Unsweetened cocoa powder (Dutch process)
  • 1 ½ tsp (8 g) Baking soda
  • 1 tsp (5 g) Baking powder
  • 1 tsp (5 g) Fine sea salt (for cake)
  • 2 large eggs, room temperature
  • 1 cup (240 ml) Buttermilk, room temperature
  • ½ cup (120 ml) Vegetable oil
  • 1 tsp (5 ml) Vanilla extract
  • 1 cup (240 ml) Hot black coffee or water
  • 1 cup (225 g) Unsalted butter, very soft (for buttercream)
  • 1 cup (250 g) Smooth peanut butter (stable brand)
  • 4 cups (480 g) Powdered sugar, sifted
  • 4-6 tbsp (60-90 ml) Heavy cream or whole milk
  • ½ tsp (3 g) Fine sea salt (for buttercream)
  • 4 oz (115 g) Dark chocolate, chopped (55-65% cocoa solids, for ganache)
  • ½ cup (120 ml) Heavy cream (for ganache)

Instructions:

  1. Preheat oven to 350°F (175°C). Grease and flour three 8-inch round cake pans, lining the bottoms with parchment paper discs.
  2. In a large bowl, whisk together the flour, sugar, cocoa powder, baking soda, baking powder, and salt (dry ingredients).
  3. In a separate bowl, whisk together the eggs, buttermilk, oil, and vanilla extract (wet ingredients) until fully combined.
  4. Pour the wet mixture into the dry ingredients. Mix on low speed until just combined.
  5. Carefully pour the hot coffee or water into the batter. Mix just until smooth (the batter will be thin, which is normal). Do not overmix!
  6. Divide the batter evenly between the three prepared pans. Bake for 30–35 minutes, or until a skewer inserted into the center comes out clean.
  7. Let the cakes cool in the pans for 10 minutes, then invert them onto a wire rack to cool completely.
  8. For the buttercream: In a stand mixer, beat the softened unsalted butter and peanut butter together on medium speed until light and fluffy (about 3 minutes).
  9. Gradually add the sifted powdered sugar, one cup at a time, mixing on low speed until incorporated, then increasing speed to medium.
  10. Add the vanilla extract, salt, and 4 tablespoons of heavy cream. Beat until fluffy. Add remaining cream, one tablespoon at a time, until the desired spreading consistency is reached.
  11. For the ganache: Heat the heavy cream until just simmering. Pour the hot cream over the finely chopped dark chocolate. Let it sit for 5 minutes.
  12. Whisk the chocolate mixture gently from the center outwards until smooth and glossy. Set aside to cool to room temperature; it should be thick enough to slowly drizzle.
  13. Once cakes are cool, level the tops if necessary using a serrated knife.
  14. Assembly (Crumb Coat): Stack the cake layers, frosting between each layer. Apply a thin layer of buttercream all over the exterior of the cake (the crumb coat). Refrigerate for 20-30 minutes until the crumb coat is firm.
  15. Final Coat: Apply the remaining peanut butter buttercream for the final, smooth coat.
  16. Drizzle and Set: Transfer the cooled ganache to a piping bag. Drizzle the ganache around the edge of the cake so it gently drips down the sides, then cover the top. Chill for a final 15 minutes before slicing and serving.