Recipe tips: Opéra

Hello fork musketeers!

Today we'll be taking a look at the elegant Opéra.

(No I didn't forget to pipe the name on it. I ran out of time and the chocolate was already hard and put away, so I simply omitted it)

So let's look at the anatomy of an Opéra cake. It consists of three or four different parts: joconde sponge cake; chocolate ganache; coffee flavoured buttercream and pâte à glacer (frosting paste). The last is optional and you could totally use chocolate ganache instead.

Your opéra components

So joconde cake is exactly like making lady fingers, except you're incorporating the almond powder with the eggs. When that's whipped, reserve and make meringue and incorporate the meringue into the batter. You'll want to incorporate the meringue as best you can in as little turns as possible. Chunks of meringue will make your joconde rise unevenly.

At school we lined small trays with parchment paper and poured the batter into the trays. Parchment paper will really help with the assembly, so I highly recommend you use it. Once you bake it, take it off the tray (thanks to the parchment paper) and put a towel on top. The steam will help make the sponge more moist and soft.

In the mean time, you can make your ganache and buttercream. Let's take a closer look at the ganache.

Ganache troubleshooting tips

Ganache. So simple and delicious, but it's not the most beautiful food to watch while it's being made. In fact, if you just decide to jump into making ganache without knowing, you would think you screwed it up. Don't fret; just keep mixing and it will come togther.

That being said, sometimes your ganache will "break" even if you've done all the right things.

Notice the clumpy bits.

It's really discouraging when you've made ganache before and, because the stars and the moon aligned on the night of a red moon in summer, your ganache breaks. It totally sucks... but it can be fixed! Yay!

The reason why a ganache breaks is usually because there's not enough fat; either from the lack of fat in the chocolate and/or the lack of fat in the cream/milk. So check this out: all you need is some cold cream and...

Top part is the broken ganache.
The bottom is the ganache with added cream.

... look at the world of difference! You show that ganache who's boss!

Assembling your Opéra

Opéra cake is a layered cake. So you have to cut your joconde into three, more-or-less, similar pieces and your layers need to go like this:

Going from the bottom to the top:

1. Joconde (+coffee syrup)
2. Coffee buttercream
3. Joconde (+coffee syrup)
4. Ganache
5. Joconde (+coffee syrup)
6. Coffee buttercream
7. Frosting paste or chocolate ganache.

The slight exception is the bottom. If you want, you can apply some frosting paste on the crust-side of your joconde before flipping it over. I know on my very first Opéra cake I didn't put anything; so it's up to you.

Protip: you should assemble this cake crust side down. In other words, you're going to be flipping your joconde so the golden and delicious part is always facing the ground. You should be using the parchment paper as a way to grab your slightly tacky joconde and peeling off the parchment paper before you put the syrup. You assemble it this way so the coffee syrup can penetrate the joconde more easily.

When you're applying the syrup, be very liberal with it. You don't have to be super liberal with the layer on the very bottom but for the middle and the top layer you shouldn't be afraid to use your syrup. You know you're done when the coffee syrup is not immediately absorbed into the sponge or you can cut small slits to see if the joconde is brown from the syrup.

As a rule of thumb, opéra is a very, very flat cake. Chef said the cake shouldn't be more than 2-3cm or 0.75"- 1 1/8"~ high, so be careful not to make your joconde too thick. When you're done, pop your opéra in the fridge and let the buttercream firm up before you apply the top layer.

Protip: Take special care to put a bit more buttercream/ganache in the corners and edges of the cake. Those areas tend to be overlooked. Also, make sure the top buttercream layer is very smooth; any obvious bumps and/or imperfections are going to show through the chocolate layer on top. Don't fret if you have minor spatula streaking though.

The trickiest part about this is when you need to put the frosting paste on top. You can add a bit of vegetable oil to make it more runny. If you're using chocolate ganache, I popped mine in the microwave to warm up so it was runny. This step has to be done quickly and with the least amount of fiddling as possible; the more you touch it, the uglier your top will be. As you pour, don't be afraid if it dripples off the side. You're going to be cutting the edges anyway!

Protip: When you put your ganache/frosting paste on top, make sure your cake isn't super cold. It'll cause your ganache/paste to set much more quickly and make it harder to get a smooth finish.

The next step is cutting your opéra. 

Chef's Opéra being used as a demo.

Whether you used chocolate ganache or frosting paste, you need a hot knife to effectively cut it. You want the hot knife to melt the chocolate on top, then when the knife melts through the chocolate, you may apply pressure to cut the rest of it. This is more crucial if you used frosting paste; when it sets it becomes hard so it will snap if you apply too much pressure. And that will make us both upset. So! Remember to use a hot knife to melt the chocolate and be patient.

Dat cutting action.

What you do with the extra bits is up to you.

In general, Opéra is an extremely rich dessert that is best eaten in small quantities. The exact proportion of the square/rectangle is up to you. If you're more into numbers, Chef told me the general serving size is between 80-120grams.

The width on the right pieces bothered me so much that
I ended up cutting them into squares. I have no regrets.

If you notice on the bottom row, 5th piece to the left:

... That piece cracked because I didn't let the knife melt the chocolate and that area was a little thin. So when you're cutting you must have a super hot knife and patience, patience, patience! Plus wipe your knife between each cut.

Protip: I found continuously diving your cake into halves (half/quarter/eighth etc) will help you get more even pieces.

Just for fun, let's do a bit of comparing:

My very first opera cake.

Opéra I made at school

Which do you think is better?