Sunday, 28 July 2013

Hazelnut Gateau l'Opera

Because everything in my work life is about creating elegance and beauty with the utmost care and precision, I have to admit that at home, more often than not, I opt for speedy suppers over pretty plates. Most days, the evening meal is something quickly rustled up out of the fridge, from whatever needs to be used up with the most urgency.

Don’t get me wrong, I like pulling out the stops when friends and family come over. It always feels, somehow, impolite and unwelcoming not to go to at least some effort for those you like and care for. But for average days, I make simple and unfussy food without much forethought or planning.

But sometimes, just sometimes, it’s nice to go a bit fancy, even without a party of guests to cook for. To treat yourself and your partner to a cosy date at home with posh grub and plenty of Prosecco, for no particular reason, other than because you can.

If you’re the type that needs a more solid excuse for a celebration, then the arrival of Prince George can be occasion enough. Republicans can raise a glass and a dessert fork to the warm weather instead. Whatever your feelings about the latest royal addition – joy, ambivalence or disregard – this Gateau l’Opera can unite us all!

This indulgent French dessert cake is the perfect celebration fare, whether you have a reason to party or not. It’s certainly fit for royalty, but once you taste it, I can guarantee you’ll want to keep it all to yourself.

Hazelnut Opera Cake (GF)

Opera Cake is traditionally made with thin layers of light almond sponge (called Joconde), soaked in coffee syrup and layered with French buttercream and chocolate ganache. I love the classic combination of chocolate and coffee, but I can never resist a hazelnut. So, I decided to combine all three and boy, oh boy, am I glad that I did.

Preheat your oven to 180°C (160°C Fan)/350°F/Gas Mark 4 and line two 15 x 10-inch roulade trays with baking parchment.

For the Hazelnut Joconde

2 egg yolks
2 whole eggs
5 egg whites
A pinch of salt
50 g caster sugar
40 g melted butter
50 g rice flour, sifted
175 g icing sugar, sifted
175 g ground hazelnuts

For the crisp chocolate base

50g dark chocolate, tempered

For soaking the joconde 

150ml espresso, with 1 tbsp. caster sugar dissolved into it, before leaving the coffee to cool.
150ml hazelnut liqueur (I used Frangelico)

For the French buttercream

200g caster sugar
2 tbsp. water
200g unsalted butter
3 egg yolks
1 tbsp. espresso coffee
1 tbsp. hazelnut liqueur

For the ganache

250g dark chocolate, chopped
250ml single cream
25g soft, unsalted butter

Plus gold or silver leaf to decorate (optional)

To make the Joconde

Whisk the egg yolks, whole eggs and icing sugar together until pale and fluffy. Add the ground hazelnuts and continue whisking on high speed for about 5 minutes. Stir in the melted butter and rice flour until thoroughly incorporated. In a separate, clean and oil-free bowl, whisk the eggs whites and salt until at the soft peak stage. Whisk in the caster sugar in two stages and continue whisking until the meringue is stiff and glossy. Add a third of the meringue to the hazelnut mixture and vigorously stir in to slacken the batter. Fold in the remaining meringue and pour the mixture into your prepared roulade trays. Use a palette knife to smooth the mixture out thinly.

Bake in your preheated oven for 8 – 12 minutes, or until an inserted skewer comes out clean. Keep a close eye on it, as it can burn very quickly. Remove from the oven and leave to cool in its tin on top of a wire rack for about 10 minutes before turning out of its tin on to the rack to leave to cool completely.

To make the French coffee and hazelnut buttercream

Place the sugar and water in a pan and place over a gentle heat until the sugar has dissolved. Increase the heat slightly and simmer until it reaches the soft ball stage (this happens at around 120°C).

Whisk the egg yolks in a bowl. Trickle the hot syrup into the eggs, whisking all the time. Once the mixture is pale and fluffy, leave it to cool a little before whisking in the butter. Whisk in the coffee and liqueur and leave to cool completely.

To make the chocolate ganache

Place the chopped chocolate in a heatproof bowl. Scald the cream in a saucepan and pour it over the chocolate. Leave to stand for 1 minute before mixing it in with a rubber spatula until all the chocolate has melted. Whisk in the butter and leave to cool slightly.

To assemble the Opera Cake

Trim both the sheets of Joconde into equal sized rectangles and cut each rectangle in half so that you have 4 equal sized pieces of cake.

Turn one piece of Joconde over and paint it with 50g of tempered chocolate to make a crisp chocolate base. Leave to set at room temperature before turning it over on to a sheet of baking parchment resting on a large chopping board.  Use a pastry brush to apply a liberal amount of coffee syrup – enough so that the cake turns brown.

Evenly spread a layer of buttercream about a ¼ inch thick over the coffee-soaked sponge. Place another layer of Joconde on top. Make sure the layers are very even. Soak the cake in hazelnut liqueur.  Spread a thin, even layer of ganache over the top. Leave to set at room temperature, or, if you’re feeling impatient, pop it in the freezer for 10 minutes to firm up. Top with a third layer of Joconde and soak with more coffee syrup. Spread with another layer of buttercream before placing the final layer of Joconde on top. Soak the top layer in hazelnut liqueur and top with more ganache. Leave to set at room temperature – do not be tempted to speed things up with the fridge/freezer here, as it could affect the sheen on your topping.

Once set, dip a long, sharp knife in hot water. Wipe it dry and trim each edge neatly, dipping the knife in hot water and drying it before cutting each new edge. Save these as a delicious cook’s treat for later. You can also attach a few flakes of edible gold or silver leaf for a little extra glamour.


  1. Just discovered your utterly beautiful blog. This opera cake looks incredible - so neat and inviting!

    1. Thank you so much, how lovely of you to say! I'm a keen reader of your blog - your photography and recipes always look so temptingly delicious.

  2. Yum, this sounds amazing...Super delicious i bet. Thanks for sharing.