Opera cake

Makes 8 Cakes, Bread and Pastries

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Method

Preheat the oven to 180C/160C F/Gas 4. Line a 30 x 40cm or two 30 x 20 cm baking trays with baking paper.

For the joconde sponge, use an electric mixer fitted with the whisk attachment to whisk the grounds almonds, icing sugar and whole eggs until pale and fluffy.

Wash and dry the whisk attachment, put the egg whites and caster sugar in another bowl and whisk to form a glossy meringue. Fold the meringue into the almond mixture, then add the flour and melted butter and stir until just combined.

Spread the batter evenly over the baking tray or trays and bake for 15–18 minutes or until pale golden brown. Allow to cool completely on the trays, then cut the sponge into four 15 x 20cm rectangles.

For the chocolate crémeux, put the gelatine in a small bowl of iced water and set aside for 5 minutes, then squeeze out any excess water and set aside.

In a medium bowl, whisk the egg yolks and sugar until just combined. Bring the milk and vanilla to a simmer in a pan, then pour it over the egg yolk mixture, whisking to ensure you don’t scramble the egg. Return this custard base to the pan and cook until slightly thickened or it reaches 70C on a cook’s thermometer. Remove from the heat and add the softened gelatine, stirring until completely melted.

Melt the chocolate in a microwave-safe bowl on medium in 30-second intervals until completely melted. Stir the chocolate into the custard
base, then add the butter and use a stick blender to blend until smooth and glossy. Cover the surface of the crémeux with plastic wrap and put it in the fridge to chill.

For the buttercream, combine the egg whites, sugar and coffee in the heatproof bowl of an electric mixer. Sit the bowl over a pan of simmering water (don’t let the water touch the bowl) and cook, stirring
constantly, until the mixture reaches 70C on a cook’s thermometer or until the sugar has completely dissolved.

Use the whisk attachment of the mixer to whisk the mixture until stiff peaks form and the bowl is cool to touch. Add the butter and whisk until the mixture emulsifies. Don’t worry if it splits - just keep mixing and it will come back together, becoming glossy and thick.

For the coffee syrup, combine all the ingredients in a pan with 50ml water and bring to the boil. Remove from the heat and set aside to cool slightly.

For the ganache, combine the chocolate, cream and butter in a microwave-safe bowl and microwave in 30-second intervals until completely melted. Blend the ganache until smooth and shiny using a stick blender.

To assemble, take one layer of the joconde sponge and brush it with coffee syrup until completely coated. Spread half the chocolate crémeux over the top in a thin, even layer. Top with a second layer of sponge and brush it with syrup. Spread half the coffee buttercream over the sponge. Top with the third layer of sponge, brush with syrup and spread with the remaining crémeux. Top with the final layer of sponge, brush with syrup and spread with the remaining buttercream. Transfer to the fridge to set for at least 4 hours or overnight if possible.

Spread a thin layer of ganache over the top of the cake and put back in the fridge for 30 minutes to set. Slice and serve.