Step-by-Step Instructions

1. 1.Prepare Dry Ingredients

   Sift the all-purpose flour and cocoa powder into a large bowl. Set aside.

2. 2.Cream Butter and Sugar

   In a separate bowl, cream the unsalted butter and granulated sugar using an electric mixer until light and fluffy, about 2-3 minutes.

3. 3.Add Vanilla and Eggs

   Add vanilla extract to the creamed butter and sugar. Then, add the eggs one by one, mixing well after each addition until fully incorporated and the mixture is smooth.

4. 4.Melt Chocolate and Brew Espresso

   Melt the dark chocolate using a double boiler method. Brew 100ml of espresso.

5. 5.Combine Wet and Dry Ingredients

   Pour the melted dark chocolate into the butter-sugar-egg mixture and mix until combined. Add half of the brewed espresso and half of the sifted flour-cocoa mixture. Mix until just combined. Repeat with the remaining espresso and flour-cocoa mixture, mixing until the batter is smooth and uniform.

6. 6.Bake the Cake

   Pour the cake batter into a greased and floured 20cm springform pan. Bake in a preheated oven at 180°C (350°F) for 50 minutes, or until a wooden skewer inserted into the center comes out clean.

7. 7.Cool and Chill the Cake

   Once baked, remove the cake from the oven and let it cool in the pan for 10-15 minutes. Then, carefully remove it from the pan and transfer it to a wire rack to cool completely. Once fully cooled, wrap the cake tightly in cling film and refrigerate for at least 6 hours (or overnight) to make it easier to handle and slice.

8. 8.Prepare the Syrup

   In a small saucepan, combine 100g of granulated sugar and 100ml of water. Heat over medium heat, stirring constantly, until the sugar completely dissolves and the mixture comes to a boil. Remove from heat and let it cool slightly. Brew 50ml of espresso and add it to the sugar syrup. Stir well and set aside.

9. 9.Prepare the Chocolate Buttercream

   In a large bowl, whip the softened unsalted butter using an electric mixer until light and fluffy. Gradually add the icing sugar, a spoonful at a time, mixing on low speed until incorporated, then increase speed and whip until smooth. Add the vanilla extract and a pinch of salt. Pour in the melted dark chocolate and fold it into the buttercream until fully combined and smooth.

10. 10.Assemble the Cake

    Carefully slice the chilled chocolate cake horizontally into three equal layers. Place the first cake layer on a serving plate or cake board. Brush generously with the prepared syrup. Spread a thick layer of chocolate buttercream evenly over the first cake layer. Place the second cake layer on top, brush with syrup, and spread another layer of buttercream. Top with the third cake layer and brush with the remaining syrup.

11. 11.Crumb Coat and Chill

    Apply a thin layer of chocolate buttercream all over the top and sides of the cake. This is called a 'crumb coat' and helps to seal in any loose crumbs. Refrigerate the cake for 30 minutes to allow the crumb coat to set.

12. 12.Apply Final Buttercream Layer

    After 30 minutes, remove the cake from the refrigerator. Apply a thicker, final layer of chocolate buttercream evenly over the top and sides of the cake, smoothing it out with an offset spatula or bench scraper.

13. 13.Prepare the Chocolate Ganache

    In a small saucepan, heat the milk until it just begins to simmer. Place the chopped dark chocolate in a heatproof bowl. Pour the hot milk over the chocolate. Let it sit for 2-3 minutes, then stir gently until the chocolate is completely melted and the ganache is smooth and glossy.

14. 14.Pour Ganache and Decorate

    Pour the warm chocolate ganache over the top of the cake, allowing it to drip down the sides for a rustic look. Use an offset spatula to gently spread the ganache if needed. Immediately decorate the top of the cake with fresh strawberries, blueberries, and mint leaves before the ganache sets.

15. 15.Serve

    Refrigerate the cake for at least 1 hour to allow the ganache to set. Slice and serve your delicious chocolate cake!