Preheat and prepare the pans

• Preheat the oven to 175 °C.
• Grease and line the cake pans with baking paper.

Mix the dry ingredients

• Sift the flour, cocoa powder, baking powder, baking soda and salt into a bowl.
• Whisk in the sugar until evenly combined.

Mix the wet ingredients

• Whisk the eggs, vegetable oil, buttermilk and vanilla extract in another bowl until smooth.

Make the cake batter

• Pour the wet ingredients into the dry ingredients and whisk until just combined.
• Slowly whisk in the hot water until the batter is thin and glossy.

Bake the cake layers

• Divide the batter evenly between the prepared pans.
• Bake until a skewer inserted in the centre comes out clean.
• Cool in the pans, then turn out onto a cooling rack.

Make the chocolate buttercream

• Beat the softened butter until pale and fluffy.
• Gradually add the powdered sugar and beat until smooth.
• Beat in the melted chocolate and heavy cream until light and spreadable.

Make the ganache

• Heat the heavy cream in a saucepan until just simmering.
• Pour it over the chopped chocolate and let stand, then stir until smooth and glossy.
• Let the ganache cool slightly before dripping.

Level and split the layers

• Trim the domed tops of the cakes so they are flat.
• Cut each cake into thin layers to get eight layers in total.

Assemble the cake

• Place a cake layer on the cake stand and spread with buttercream.
• Pipe a ring of buttercream around the edge and fill the centre with berry jam.
• Repeat with the remaining layers, finishing with a layer of cake.

Crumb coat and chill

• Cover the whole cake with a thin layer of buttercream.
• Chill until the frosting is firm.

Frost and add the ganache drip

• Cover the chilled cake with the remaining buttercream and smooth the top and sides.
• Spoon the ganache around the top edge so it drips down the sides.
• Spread ganache over the top and smooth it.

Decorate and serve

• Arrange the fresh berries on top of the cake.
• Chill briefly before slicing.