Method of work
To prepare the sponge layer
Preheat the oven to 220°c. Line a 20 x 30cm baking pan with parchment paper. In a large bowl, sift together the flour and icing sugar, then add the powdered almonds.Mix well. Add the eggs, one at a time, and beat until pale. Add the melted butter. Beat the egg whites until stiff, then gradually add sugar and continue beating until stiff peaks are obtained. Add one-third of the beaten egg whites to the almond mixture, mixing well, and then incorporate the remainder, folding until just combined. Pour onto the baking tray and spread evenly. Bake for 6 to 8 minutes, or until golden and springy when touched. Loosen the edges with a knife and carefully turn out onto a wire rack covered with a sheet of parchment paper. Allow to cool. Place finely chopped chocolate in a heatproof bowl and set aside. Bring the milk and 30ml of the cream to a boil. Pour the hot liquid onto the chocolate. Wait 30 seconds, and then add the butter and mix until smooth. Let cool until a spreadable consistency is obtained.
To prepare the coffee syrup
Place the sugar and 90ml of water in a pan and stir until dissolved. Bring to a boil and add the coffee.
To prepare butter cream
Place the sugar and 3 teaspoons of water in a heavy skillet and make sugar syrup, stir until the sugar is completely dissolved and then boil, without stirring, until syrup reaches soft-ball stage, between 116 and 118°c. Beat the egg white until soft peaks are obtained. Continue beating while incorporating the hot syrup. Beat until mixture is cold. Dissolve instant coffee in 1 teaspoon of boiling water, cool and add to butter. Add one half of the egg-white mixture and beat well, then gently fold in the remainder until well combined. Using a sharp knife, divide the sponge into three equal sections and carefully peel off parchment paper from sections. Each should be 10 x 20 cm (4 x 8 inches). Soak the first section with one-third of the coffee syrup, and then spread over it half of the butter cream. Place the next section of sponge on top, then soak with coffee syrup and spread with half of the Ganache. Place the last section on top, soak with remaining syrup and spread with the rest of the butter cream, taking care to smooth the surface. Chill until butter cream firmly set. Melt the rest of the Ganache over a pan of very hot water. Bring the remaining cream to the boiling point and incorporate into Ganache. Allow to cool until a smooth, spreadable consistency is obtained and spread over top of cake.
Method of work and service
For the sorbet
Bring the water and sugar to the boil in a saucepan. Once the sugar has dissolved, simmer for 5 minutes to produce a stock syrup. Remove from the heat and allow to cool, and then add the orange juice and the lemon juice. Chill the mixture, then churn in an ice cream machine and place in the freezer.
To serve
Remove the sorbet from the freezer about 20 minutes before serving to allow it to soften. Cut the Opera into suitable portions and serve with the blood orange sorbet, some orange compote and a fine strip of praline on top of the Opera.?