This is definitely a cake for a special occasion. Although it does take time to make, I can promise you the results are worth the effort – it’s quite a show-stopper. The chocolate sand adds an extra textural element to the buttercream filling, but you can omit this if you like. If your chocolate ganache ‘splits’ (which has happened to me many times, normally when I’ve really splurged on expensive chocolate), it’s really easy to remedy – just whisk the ganache with a hand-held blender, and in no time it will be restored to its former shiny, glossy self.
1 tbsp good-quality instant coffee granules
1/3 cup (80ml) boiling water
300g unsalted butter, softened
300g caster sugar
6 free-range eggs, lightly beaten
1/4 cup (60ml) Frangelico
2 tbsp milk
3 cups (450g) plain flour
2 tbsp baking powder
1½ tbsp cocoa powder
chocolate liqueur (optional), to serve
375g unsalted butter, softened
1/3 cup (55g) icing sugar, sifted
105g good-quality dark chocolate
3 tbsp milk
2 tbsp Frangelico
CHOCOLATE SAND (OPTIONAL)
1/3 cup (45g) hazelnuts
50g meringue (I use shop-bought meringue shells)
50g good-quality dark chocolate (60–70% cocoa solids)
135g good-quality dark chocolate (60–70% cocoa solids), broken into small pieces
3/4 cup (180 ml) pure (whipping) cream
1 tbsp Frangelico
Preheat the oven to 180˚C fan-forced. Scatter the 250 g of hazelnuts on a baking tray and roast in the oven for 10 minutes until lightly golden brown, being careful not to burn them. Rub off the skins in a clean, dry tea towel and coarsely crush the nuts. Set aside. (If you are making the chocolate sand, roast the extra 45 g hazelnuts for this at the same time, then rub off the skins and set the nuts aside in a separate bowl.)
Grease and line three 20 cm springform cake tins.
Dissolve the instant coffee granules in the boiling water, stirring well to combine, then allow to cool. Using an electric mixer, beat the butter and sugar on a medium–high setting for 8–10 minutes until very light, fluffy and pale. Turn the speed down to medium and gradually add the beaten eggs in four or five additions. Continue to beat until incorporated. Add the Frangelico and milk and beat for a further minute or so, then add the cooled coffee mixture and beat on low speed just to combine all the ingredients together.
Sift the flour, baking powder and cocoa into a bowl and combine, then add to the cake mixture and beat until everything is incorporated. Spoon the cake batter into the prepared tins and smooth the tops. Bake for 40–50 minutes, swapping the tins halfway through the cooking time to ensure even cooking. When cooked, the cakes should be golden, and a skewer inserted into the center should come out clean. Allow to cool a little before removing the cakes from the tins and transferring them to wire racks to cool completely.
To make the chocolate buttercream, use an electric mixer to beat the butter and sugar until light, fluffy and pale (about 8–10 minutes). Meanwhile, bring a small saucepan of water to a gentle simmer and melt the chocolate in a small heatproof bowl that fits snugly over the pan without touching the water, stirring occasionally. Carefully remove the bowl from the heat and allow to cool slightly, then pour into the butter and sugar mixture. Stir to combine, then stir in the milk and Frangelico.
If making the chocolate sand, place the 45 g of roasted hazelnuts and meringue shells in a food processor and blitz to a fine meal, then transfer to a medium-sized heatproof bowl. Bring a small saucepan of water to a gentle simmer and melt the chocolate in a small heatproof bowl that fits snugly over the pan without touching the water, stirring occasionally. Pour the melted chocolate over the hazelnut and meringue mixture and mix together using the edge of a spatula until evenly coated. The whole lot should look like, well, chocolate sand!
To make the chocolate ganache, place the chocolate in a heatproof bowl. Bring the cream to a slow boil in a small saucepan over low heat. Once boiling, remove from the heat and pour the cream over the chocolate. Leave to stand for 5 minutes, then stir to combine. Stir in the Frangelico and set aside
To assemble the cake, use a sharp bread-knife to carefully trim off the rounded tops of the three cakes to provide flat surfaces for the buttercream. Place the first (bottom) cake on a clean worktop and spread a layer of buttercream on top, then sprinkle with a good layer of chocolate sand, if using. Add the second cake and repeat with buttercream and chocolate sand. Top with the third cake. Using a palette knife, cover the entire cake with a thin layer of buttercream and place in the fridge to chill. After about 15 minutes, remove the cake from the fridge and cover with chocolate ganache.
Return to the fridge to chill for a further 5 minutes, then remove and sprinkle the top and sides of the cake with the crushed hazelnuts. Serve with a small drizzle of chocolate liqueur, if you like.