It may just be my lack of sophistication, but like the Strawberry Mirror Cake, I had never heard of the cake at the centre of this month's Daring Bakers Challenge until the challenge was put to us by Ivonne & Lis. Boy am I glad it was bought to my attention though! I'm not usually a fan of sponge style cakes at all, but when they are this delicious (possibly due to the copious amounts of yummy fillings), who could resist? Not me that is for sure!
One of the main rules for this challenge was that we had to stick to 'light' coloured flavourings, as this months challenge is being dedicated to Barbara at Winos & Foodies who holds an annual Taste of Yellow event for Livestrong day, which is in May this year. I made it for my mum's birthday so I opted to flavour mine with one of her favourite nuts - pistachios. To further the middle eastern theme I added some honey and rosewater as well. It was a great combination!
After last month's challenge, the Opera Cake was definitely much more challenging and back to the usual style of challenges with a billion different components and steps (be warned, the recipe below is quite long!), but I wouldn't have it any other way. I love a challenge and it is always so rewarding to look at your creation at the end and see people's reactions. Apart from the fact that this cake took up a lot of time (but it was a welcome break from all the assignments I have been doing lately)and being rather expensive (it cost me at least $50 for ingredients, and some items I already had in my cupboard), it was also challenging because I haven't had much luck with sponge cakes in the past. The sponge layer on my Strawberry Mirror Cake had a rubbery layer on the bottom and I even managed to very badly burn one of the two sponges that we had to cook for this challenge - even though they were both in the oven at the same time! I suppose the upside is I got some extra practice in making sponge cakes though...
So, 15 eggs and truckloads of butter, cream and white chocolate later, I ended up with this beautiful cake...
Honey, Rosewater & Pistachio Opera Cake Serves 20
Joconde (Almond Sponge)
In a food processor grind 2C blanched almonds & 2Tbsp plain flour until the mixture is fine. Attach the paddle attachment to the stand mixer and beat 225g almond meal (that was just made in the food processor), 2C icing sugar & 6 large eggs on medium speed until light and voluminous, about 3 minutes. Add 1/2C minus 2Tbsp plain flour and mix on low speed until just combined (Don't overmix!).
Using a rubber spatula, gently fold the meringue into the almond mixture and then fold in 3Tbsp melted and cooled, unsalted butter. Divide the batter between the prepared trays and spread evnly over the entire surface of each pan. Bake the cakes until they are lightly browned and springy to the touch, around 5-9 minutes. Put the pans on a heatproof counter and run a sharp knife along the edges of the cake to loosen it from the pan. Cover with a sheet of baking paper, turn the pans over and unmould. Let the cakes cool to room temperature before using. Can be kept airtight at room temperature for up to 1 day.
Honey & Rosewater Soaking Syrup
Combine 1/2C water, 1/3C sugar, 2Tbsp manuka honey & 1Tbsp rosewater essence in a small saucepan and bring to the boil. Remove from heat and let cool to room temperature before using. Can be made up to 1 week in advance and kept covered in the refrigerator.
Vanilla & Honey Buttercream
Combine 1C sugar, 1/4C water, 2Tbsp manuka honey & 1tsp vanilla bean paste in a small saucepan and warm over medium heat until the sugar dissolves. Continue to cook, without stirring, until the syrup reaches 107C on a candy thermometer. Remove from the heat.
While the syrup is heating, whisk together 1 large egg & 1 large egg yolk at high speed in the bowl of a stand mixer using the whisk attachment, until pale and foamy. Reduce mixer speed to low and add syrup very slowly. Raise the speed to medium-high and continue beatinguntil the egs are thick and satiny and the mixture is cool to the touch, about 5 minutes.
While the egg mixture is beating, place 200g unsalted butter, at room temperature in a bowl and mash it with a spatula until you have a soft, creamy mass. Add chunks with the mixer on medium sped and raise to high speed once all butter has been incorporated, beat until thick and shiny. Refrigerate, stirring often, until it is set enough to spread and be topped with another layer of cake, around 20 minutes. Alternatively, make ahead and refrigerate for up to 4 days or freeze for up to 1 month.
White Chocolate & Semillon Mousse
Melt 200g good quality white chocolate & 3Tbsp heavy cream in the microwave. Add 1Tbsp semillon, stir thoroughly and set aside to cool completely. In the bowl of a stand mixer whip 1C heavy cream until soft peaks form. Gently fold the whipped cream into the cooled chocolate to form a mousse. Refrigerate until it is spreadable.
White Chocolate & Vanilla Glaze
Melt 400g good quality white chocolate & 1/2C heavy cream in the microwave. Whisk gently until smooth. Let cool for 10 minutes before using.
Assembly of the Cake
Cut each sponge cake into 2 pieces: one 20cm square & one rectangle 20cm x 10cm. Place one of the squares on a platter and moisten with soaking syrup. Spread 3/4 of the buttercream over this layer and top with the two rectangular sponge cake pieces. Soak with more syrup and spread remaining buttercream over this layer. Roughly chop 150g (?) pistachio nuts and sprinkle half of these over the top of the buttercream, making sure it shows around the edges. Top with the other square of sponge cake, using the remaining syrup to soak it. Refrigerate until very firm, at least half an hour.
Spread the mousse evenly over the top of the last layer of sponge and refrigerate for at least 2-3 hours to give the mousse the opportunity to firm up. Once the glaze has cooled (it is best to make it at the last minute) pour it over the mousse and using a long metal spatula, smooth it out into an even layer. Sprinkle with remaining pistachio nuts, concentrating on the centre. Place the cake in the refrigerator for 30 minutes to set. Serve the cake slightly chilled.