Gâteau opéra cake
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Makes: 12 portions
 
Ingredients
Joconde almond cake
  • 180 gr ground almonds
  • 260 gr sugar
  • 6 eggs
  • 6 egg whites
  • 60 gr butter
  • 90 gr white flour
Coffee crème
  • 500 gr milk
  • 1 tbspn instant coffee
  • 100 gr white sugar
  • 3 egg yolks
  • 70 gr flour
  • 250 gr soft butter
Opera ganache
  • 165 gr double cream
  • 240 gr dark chocolate
  • 75 gr soft butter
Chocolate coating
  • 168 gr water
  • 303 gr sugar
  • 175 gr double cream
  • 54 gr cacao powder
  • 12 gr gelatine
Garnish
  • 50 gr white chocolate
Instructions
Joconde almond cake
  1. Preheat the oven to 180°C. Cream half the sugar with the whole eggs. Whip the egg whites to stiff peaks adding the remaining sugar gradually. Melt the butter. Mix the butter, flour and the ground almonds with the beaten eggs and fold in the stiff egg whites.
  2. Spread the batter on the trays lined with baking paper and spread until 1 cm thick. Bake in the oven for 10 to 12 min or until cooked and golden. Remove from the oven, turn upside down on a second sheet of baking paper, and allow to cool to room temperature. Peel away the old baking paper and cut out 4 rectangles that are the size of the opera later.
Coffee crème
  1. Bring to the boil most of the milk, instant coffee and half the sugar. Mix the egg yolks with the remaining sugar and flour and the cold milk you kept back.
  2. Pour this in the hold milk and boil whilst stirring until thickened. Add half of the soft butter bit by bit and using a whisk, allow it to emulsify with the warm but not boiling coffee cream. Pour in a clean container, cover with cling film and allow to cool down to room temperature. Cream the soft butter and gradually add the coffee crème beating after each addition until combined and smooth. Set aside in the fridge to firm up for later.
Opera ganache
  1. Warm the cream and chop the chocolate. Pour the hot cream on the chocolate to melt it.
  2. Add the soft butter, stir until incorporated and set aside to cool down to room temperature for later. If the ganache is too hot, it is too runny to be used.
Assembly
  1. Place a chopping board or some sturdy cardboard on the work surface and the cake ring on top. Place the first rectangle of the almond cake on the bottom and cover with half of the coffee crème. Place on top a second disc of the almond cake and cover with half of the opera ganache.
  2. Cover with a third disc of the almond cake and the rest of the coffee crème. Allow to set in the fridge if need be and cover with the remaining opera ganache. Cover with the fourth and last discs of almond cake. Press down lightly to adhere and freeze the opera for 2 hours or overnight to set.
Chocolate coating
  1. Bring the water and sugar to the boil. Add the double cream and cacao powder, bring back to the boil and simmer for 10 min until thick and syrupy, it should coat the back of a spoon.
  2. Soak the gelatine in ample cold water. Take the pan of the heat, dissolve the gelatine in the warm liquid and allow to cool down to about 35ºC.
  3. Remove the cake ring around the cold opera and place on a raised support with a tray underneath to catch the excess chocolate glaze. Pour the coating on top of the opera and allow it to drip of the sides.
  4. Let set for 5 min and chill the opera in the fridge for a minimum of 1 hour so the coating can set.
Garnish
  1. Cut the sides off to expose the layer structure.
  2. Melt the white chocolate au-bain marie. Fill a small paper cone with the chocolate and write the word opera on the opera.
  3. Use the rest of the white chocolate to decorate the opera. Serve the opera at room temperature
Stuff to know
This recipe will make 8 large or 16 smaller portions and yield an opera measuring 30 x 20 cm.
The opera is a French pastry classic.
Rather than using a cake ring, it is possible to line a large dish of roasting tray with baking paper, letting it overhang the sides. Assemble the opera as explained above and, once frozen, use the excess baking paper as handles to lift the opera out.
It is recommended to put some cardboard under the first cake layer for additional support.
The opera needs to be frozen to make the layers set. Also, the cold opera will instantly set the lukewarm chocolate coating when it is poured on top. If the chocolate coating and or the opera are too warm, all the coating will run off. If it is too cold, it won’t distribute evenly.
The excess chocolate coating that drips of the side can be reused.

Recipe by Jeroen Valkenier Recipes at https://jpvalkenier.com/gateau-opera-2/