Ingredients:

  • 1 ¾ cups (220 g) All-Purpose Flour, sifted
  • 1 ¾ cups (350 g) Granulated Sugar
  • ¾ cup (75 g) Unsweetened Cocoa Powder (Dutch Processed)
  • 1 teaspoon (5 g) Baking Soda
  • 1 teaspoon (5 g) Baking Powder
  • 1 teaspoon (5 g) Fine Sea Salt
  • 2 Large Eggs, room temperature
  • ½ cup (120 ml) Buttermilk (or whole milk + 1 tsp vinegar)
  • ½ cup (120 ml) Vegetable Oil
  • 2 teaspoons (10 ml) Vanilla Extract
  • 1 cup (240 ml) Hot Water or Hot Coffee (very strong)
  • 24 oz (680 g) High-Quality Dark Chocolate (70–72% cacao), finely chopped or chips
  • 3 cups (720 ml) Heavy Cream (35% fat minimum)
  • 2 tablespoons (30 g) Unsalted Butter, room temperature (optional)
  • ¼ teaspoon (1 g) Sea Salt

Instructions:

  1. Prep the Tins: Preheat oven to 350°F (175°C). Grease and flour two 8-inch tins, lining the bottoms with parchment paper.
  2. Combine Dry Ingredients: In a large mixing bowl, whisk together the flour, sugar, cocoa powder, baking soda, baking powder, and salt.
  3. Mix Wet Ingredients: Add the eggs, buttermilk, oil, and vanilla extract to the dry ingredients. Mix on medium speed until just combined, scraping down the bowl.
  4. Activate the Batter: Carefully pour the hot coffee or water into the batter while the mixer is running on low speed. Mix until the batter is smooth and very liquid (it will be thin—this is correct!).
  5. Bake: Divide the batter evenly between the two prepared tins. Bake for 30–35 minutes, or until a skewer inserted into the centre comes out clean.
  6. Cool: Let the cakes cool in the tins for 10 minutes before turning them out onto a wire rack to cool completely. They must be stone-cold before assembly.
  7. Chop Chocolate: Place the finely chopped dark chocolate and the pinch of salt into a large, heatproof bowl. Add the room temperature butter (if using).
  8. Heat Cream: Heat the heavy cream in a small saucepan over medium heat until it just begins to simmer around the edges. Do not let it boil fiercely.
  9. Emulsify: Pour the hot cream immediately over the chocolate. Let it sit undisturbed for 5 minutes to allow the heat to melt the chocolate gently.
  10. Whisk: Starting in the centre, gently whisk the mixture in small circles until the chocolate melts and the mixture becomes smooth and glossy. Gradually widen the circles until all the cream and chocolate are fully emulsified into a dark, luxurious ganache.
  11. Divide and Cool: Pour 1 cup (240 ml) of the warm ganache into a separate small bowl (this is the Glaze). Cover and set the Glaze aside at room temperature.
  12. Whip the Filling: Place the remaining ganache (the Filling) in the fridge for 30–60 minutes, stirring occasionally, until it reaches a thick, spreadable, peanut-butter consistency. For a lighter filling, whip this chilled portion using a stand mixer until it lightens slightly in colour and holds soft peaks.
  13. Level: Using a long serrated knife, level the tops of the cooled cake layers.
  14. Fill: Place one cake layer on your serving plate. Spread the thickened/whipped ganache filling evenly across the top. Place the second layer on top.
  15. Crumb Coat: Use a thin layer of the remaining filling ganache to coat the sides and top of the cake lightly. This traps any loose crumbs. Chill the cake for 15 minutes.
  16. Glaze Preparation: Reheat the reserved Ganache Glaze slightly (if necessary) until it is smooth and pourable, but not hot (around 95–100°F / 35–38°C is spot on).
  17. Pour and Finish: Place the chilled cake on a wire rack set over a tray. Pour the glaze over the top, letting it run down the sides naturally. Use an offset spatula to gently smooth the top if needed.
  18. Set: Chill the finished Chocolate Ganache Cake for at least 30 minutes before serving to ensure the glaze sets firm and glossy.