Gateau L’Opera

Decadence is thine name

The Gateau L’Opera (or Opera cake) is a decadent, sexy French invention.

If you haven’t had it yet, the Opera is an almond sponge topped with coffee-infused buttercream and capped with a thick, dark chocolate ganache – but wait, it is not just one layer of cake; it is at least three stacked layers of the same! This is my most exciting bake to date! AND the longest I have ever spent on a cake (FOUR hours) ! Forgive the liberal use of exclamation marks, I am still very excited even though the cake has been absolutely decimated by the household by now.

You see, one of my life’s missions is to try my hand at making the Opera cake. This has been on my Bake Bucket List for as long as I can remember. I make no illusions to even hoping it will look as perfect as those behind the glass counters ……. but here it is; my maiden attempt at the Opera.

You do know what this means, don’t you?

The Gateau L’Opera is not as daunting a bake as it seems – it IS a home-baker-*friendly dessert! Hurrah!

*as long as you have no qualms working in humid tropical heat, on your feet for a back-breaking four hours” that is, heh heh. Closet masochist, hello!

I made the Opera for my husband’s birthday. Now, he is a tough one; he will always choose pudding over cake. I had to put my thinking cap on: what can I do to serve up a dessert that can hold lit candles, yet be texturally almost similar to pudding? If anything, the offspring were anticipating cake.

Then it hit me. The dark horse of the Bake Bucket List beckoned.

I started making this in the afternoon of his birthday, once lunch was sorted. The night before, I took notes off the Masterchef Australia Season 2 Masterclass on the Gateau Opera made by the redoubtable Gary Mehigan.

The devil is in the details; the assembly of the Opera was easy enough but the clincher was preparing each component before they could come together in a happy marriage of flavours. The Opera is certainly epic in its making: coffee essence, sugar syrup, joconde, italian meringue buttercream and ganache.

All. From. Scratch.

Coffee Essence

I started by making the coffee essence.

Chef Gary Mehigan’s coffee essence called for 6 shots of espresso and 100 g of sugar in a pot on medium heat, and slowly reduced to about half its original volume.

My coffee maker was on the blink, so I used 6 heaped teaspoons of instant coffee powder, added approximately 230 ml of water and 100 g of sugar. I left it on the stove until it was reduced by half. Initially, this hot coffee essence will not be as syrupy thick and glossy as per the Masterclass, but happily enough, left overnight in the fridge you will get the desired consistency. I obviously did not have this foreknowledge, so a cooled down syrup was what I had to work with.

Chocolate Ganache

The second thing I tackled was the ganache. This took 400 g of good dark chocolate broken up into a bowl. 300 ml of cream was then brought to a boil and poured onto the chocolate. A small knob of butter (30 g) was bunged in as well. The ganache comes together after a couple of minutes of vigorous stirring. You will have to summon all your willpower to stop slurping the hot chocolate mixture. Chill the ganache while working on the other components of the Opera.

Coffee Italian Meringue Buttercream

The third thing I took a stab at was the Italian meringue buttercream (IMB).

You will need:

500 g butter

300 g sugar

5 egg yolks

3 heaped teaspoons of coffee essence

Additional apparatus: a candy thermometer, pastry brush, stand mixer

The IMB is a real test of your multi-tasking skills.

• Put the sugar with a quarter cup of water in a pot. Attach your candy thermometer into the sugar taking care not to swish the wetted sugar to the pot sides. To prevent sugar crystals from forming, do not stir the bubbling mixture. Also, from time to time, dip the pastry brush in clean water to wash down the pot sides (where specks of heated sugar may have landed). Take the pot off the heat when the thermometer reaches the soft ball stage.
• While the sugar is underway, whisk the egg yolks in the stand mixer until they are an airy mass. Then slowly drizzle the melted sugar into the egg yolks. Keep the whisk going all the while, turn it on to almost the highest capacity. If you feel the underside of the mixing bowl, it will be very warm on account of the hot sugar syrup. Whisk until almost cool to touch. You will get fluffy white clouds in your mixer bowl. It will take about 8-10 minutes!
• While the mixer does the whisking, cube your room-temperature butter. Then drop in the butter cubes in increments. The cool-ish butter will continue to bring down the meringue temperature.
• Finally drizzle in the coffee essence.
• Taste, and swoon.
• Put the buttercream into the fridge to chill while preparing the joconde.

Joconde

I learnt a new word along the way: Joconde (“juh-qand’). The joconde is an almond foam sponge made with whole eggs; other foam sponges typically call for egg whites. An authentic Opera is made with an almond sponge, but my BakeSlave twist was to use hazelnut meal instead. I had to pulse the hazelnut meal through the food processor several times before the sifting. Even after straining it through the sieve, there was a remainder of at least 2/3 cups of hazelnut meal bits left. Because I didn’t want to chuck that and waste it, in the end I bunged it into the joconde dry mix after grinding it in the mortar and pestle. The hazelnut meal did not make the Opera gritty surprisingly enough, but I think in the future, I will use almond meal.

You will need:

4 whole eggs

4 egg whites

35 g caster sugar

150 g icing sugar

150 g almond meal (I used hazelnut meal instead)

60 g all purpose flour

30 g melted butter

• The oven needs to be pre-heated to 200° C. I had a 8 ″ x 11 ″ baking tray which I lined with baking paper. If you have a bigger capacity oven, you could easily cut your joconde baking time in half (oh, and use  9 ″ x 13 ″ trays!).
• Lay out a large piece of baking paper onto your table top. You will need to sift the icing sugar and almond meal onto the baking paper, followed by the flour. Why the baking paper? It is easier to form a funnel to pour the joconde dry mix into your egg mixture in one go.
• In a stand mixer, whisk 4 whole eggs till light and fluffy. You may want to transfer this fluffy mixture into a large mixing bowl. Let’s call this Mixt A.
• Next, whisk the 4 egg whites to a froth, then add about 1/3 of the sugar and continue to whisk until it thickens. Add the remaining sugar in steady increments until you get soft peaks. This is Mixt B.
• Add the sifted ingredients to Mixt A, and then add in the melted butter. Fold in gently using a spatula.
• Then add Mixt B to Mixt A.
• I used about a cup of the joconde mixture to spread on my lined baking tray.

Setting down the first (of five!) layers of hazelnut joconde

Chef Gary’s instructions call for the joconde to be spread very thinly, a couple of millimetres thick. I think with the larger-particled hazelnut meal, this knocked out most of the air from my Mixt B, so when I eventually spread the joconde mixture, it was quite flat. So the first couple of layers of joconde I baked weren’t as thick as I had hoped.

• Bake the joconde for up to 4 minutes. As the layer is very thin, you have to be vigilant because the edges get crisp very quickly. Depending on our oven variations, you may even have to pull your joconde out at the 3 minute mark.
• Once it is baked and cooled to the touch (won’t take long), peel off the baking paper. You may want to work on a base of baking paper (I almost ran out, hence the aluminium foil).
• Continue to bake your layers of joconde. I managed to get five layers in total out of my batter.

The Assembly

• In the Masterclass, Chef Gary coated the underside of the base joconde with ganache and let it set in the fridge. I omitted this step, totally forgot about it – but the Opera still turned out fine. If you do the ganache undercoat, when you are ready to assemble the Opera, remember that the ganache layer of the base joconde faces down.
• With a pastry brush, paint on a layer of the coffee essence on top of your base joconde. This is where I deviated from the original recipe. A “set” coffee essence is very thick, almost  like molasses. Chef Gary made a simple syrup, to which he added a few tablespoons of the coffee essence – and with that diluted syrup, he used to moisten the joconde. As my coffee essence was still fresh from the stove, it still was pourable, so I used the pure coffee essence. Yeah baby, that’s how I roll.

Painstaking job of painting on a thin layer of home-made sticky coffee essence to the first layer of baked joconde

• Then spread a generous dollop of your coffee buttercream.

Next comes the generous layer of coffee buttercream

• Then pour the ganache over the buttercream. No pictures here, because it was tricky to simultaneously manipulate the iPhone and coax the ganache to behave. The aluminium foil base turned out to be a serendipitous good choice because I had to quickly turn up the sides to create a catchment for the runny ganache.  Super. Messy.
• The first layer of the Opera is done! Next repeat the same for another two rounds. It WILL look like a right old mess but don’t fret. Chill the Opera in the refrigerator for at least an hour before you do the next step.

Nothing a bit of cocoa powder dusting can’t do to mask Master 7’s fingerprints

• Once suitable chilled, remove from the refrigerator. This rectangle needs trimming! Use a long sharp knife dipped in hot water. Slice off the gnarly sides.  Slice this cake into long rectangles (or go for squares if serving as petit fours). The following picture is our original Opera unveiled for the Birthday Boy Man later after dinner that same night. What you didn’t see is fingerprints on the far side of the cake, courtesy of curious Master 7. The following morning, I dusted on some cocoa powder to mask the fingerprints.

The unveiling just before presenting it to the Birthday Boy

There was plenty of ganache left over, almost a cup in fact. In hindsight, I could have made truffles rolled in some nuts as a garnish. But hungry (for the cake and for the last photo op), I just clumsily scooped it out to sit atop the slice of home-made Gateau L’Opera, cut into a petit four.

Perfect as a petit fours

Postscript:

This is a caffeine-fuelled cake. Unless you want your offspring bounding off your walls, keep your portions for them small, or not at all ! 😀

Bake Someone Happy ! Xoxoxo