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Alternatively, bake this quantity recipe mixture in a 20cm (8 inch) cake tin for one hour. Use the chocolate ganache to pour over cakes, blend with buttercream for cakes and cupcakes, or pipe shell and leaf decorations. Store the buttercream in the refrigerator for up to 14 days but use at room temperature. Alternatively, buttercream can be frozen for up to three months, then defrosted at room temperature.
For the layered cake:
Preheat the oven to 150°C (gas 2). Line the base and sides of 2 x 15cm (6 inch) round tins with non-stick baking parchment. Cream the butter and sugar together until light and fluffy. Add the beaten eggs in a slow and steady stream. With the mixer still on medium speed, pour in the melted chocolate until fully combined. The batter should be mousse-like. Fold in the ground almonds with a spatula or metal spoon until fully mixed. Spoon the batter into the prepared tins and level the surfaces. Bake for 45 minutes until risen with a crust that will wobble slightly when gently shaken. You cannot test with a knife for this cake – if it comes out clean the cake is overbaked.
Transfer the cake to a wire rack and cool for 15 minutes. Cover the surface with non-stick baking parchment and place in the refrigerator to chill before handling.
For the chocolate ganache:
To make the ganache, put the butter and chocolate in a heatproof bowl and melt for 1–2 minutes in the microwave on high until all but melted. Bring the cream to the boil on the hob, then pour the cream over the butter and chocolate. Stir with a wooden spoon until fully melted and combined. Leave to cool slightly.
For the buttercream:
To make the buttercream, whip the butter for 1–2 minutes until soft. Add the icing sugar in two batches and whisk until fully combined. Add the milk and whisk.
For the chocolate buttercream:
To make the chocolate buttercream used on this cake, blend half of the cooled chocolate ganache with the buttercream – you can use more or less depending on how chocolatey you like it.
Trim the top of the completely chilled cakes with a serrated knife. Use a palette knife to spread one cake generously with ganache buttercream, then invert the other on top. Fill a piping bag with buttercream and snip 1–2cm (½–¾ inch) from the end. Starting at the bottom, pipe the buttercream around the cake working your way upwards to the top. This will help protect the cake crumb and fill all the gaps.
Draw a cake scraper, held perpendicular and straight, around the side of the cake, in one smooth, controlled movement. Spread the buttercream on top of the cake with a palette knife. Chill for about 30 minutes until set.
Fill a piping bag with warm, chocolate ganache and snip 5mm (¼ inch) from the end. Drizzle the ganache around the top edge of the cake first to control the drips down the sides. Fill in the top of the cake with warm ganache using a cranked handle palette knife. Leave to set at room temperature for 30 minutes before decorating with fresh berries and edible flowers.