So at long last we get around to the opera cake tutorial I’ve been meaning to put up for a week. What can I say, I’m easily distracted by food science. And chocolate, well, it’s terribly interesting stuff. You’ll thank me for all those posts later, I promise you.
So anyway, opera cake. If at all possible, I suggest that you make up all your various components (the joconde, coffee buttercream, ganache, coffe-flavored cake syrup and tempered chocolate glaze) ahead of time and set an afternoon aside solely for the building of the cake. Because let’s face it, it’s easy to get worn out over the course of a lengthy baking or cooking project. Enthusiasm wanes with time and impatience sets in, and that opens the door to potentially catastrophic mistakes. Separating the stirring and baking phase from the building phase not only gives you a breather, it makes the assembly a whole lot more pleasurable. All the components including the joconde will keep just fine at room temperature overnight.
Begin by trimming the edges off your two joconde sheets. Once that’s done, measure them and cut them in half. The exact dimensions are less important than making sure they’re all the same size. You want four layers, which is traditional for an opera cake. You want the “up” side of the joconde layers (when they were finished baking) to remain their “up” side, as they’re more porous and will more easily absorb the syrup.
Job one is to apply a thin scraping of melted chocolate to the underside of the bottom layer. Remove it to a separate sheet of parchment, flip it over and spread the good stuff on. Let it firm for a few minutes, then place it in the refrigerator for a few more. What will this do? Besides adding still more deliciousness, it will ensure that the cake doesn’t stick to the cake board when it’s time to slice and serve. (This is an excellent, consequence-free opportunity to practice your tempering, should you be so inclined).
Flip it over onto your cake plate or cake board, chocolate side down (here again I’m going traditional and using a decorated board).
Gently peel the parchment back, center it on the board and you’re ready to go.
First thing, apply coffee syrup to your layer, and don’t be shy about it. I know what I’ve said about cake syrup in the past: it’s overused. However in this context you really want to go hog wild. Thoroughly soaking the layer will give the cake the melt-in-the-mouth texture that opera cakes in Paris are known for. Pastry chef Camille, who works in a Paris pâtisserie and makes these cakes regularly, tells me the layers should be soaked until they’re brown all the way through. So no genteel paintings of syrup. Go Jackson Pollock on the sucker.
And now for your first layer of buttercream. Take your time, and pay special attention to the edges. As with all icing and/or topping jobs, the tendency will be to pile all the good stuff up in the middle. Spread the buttercream slowly and deliberately, eyeballing it from all sides to get it as even as you can. You want it about a quarter inch thick.
Apply your next layer of cake.
Now it’s time for your middle layer of ganache. Oh yeah. Spread it thinner than the buttercream. Just a covering will do.
Apply the next layer of joconde.
Do I need to tell you what to do?
Another quarter-inch layer of coffee buttercream. Again, check for evenness all the way around as you apply it.
Then the top layer of cake. Edges getting a little sloppy? Don’t worry, you’ll trim those off later. Check again for evenness. If you have any obviously high spots, it’s OK to press them down a little with your palm at this point.
Soak, soak, soak.
And now for the top. Here you want just a thin scraping of buttercream, mostly to fill in any pits so the tempered chocolate top will lay on smoothy. Now’s a good time for a beer break, if you were wondering.
Prepare your tempered chocolate according to the tutorial. Or, if you just want to melt some bittersweet chocolate and put it on, that’s fine too (if you’ve gotten this far, you’ve already done one heck of a job). Spread it on promptly and thinly
Let the chocolate firm at room temperature for about ten minutes. Then, using a knife you’ve heated under hot tap water (then dried) slice off the edges to reveal the layers. (Keep and hide those trimmings, kids. The pastry chef deserves a secret, greedy coffee break sometime in the next day or two).
Looks pretty good. Maybe not an Opera cake for the ages, but pretty darn decent.
Once that’s done it’s time to score the top so it doesn’t shatter later when you want to cut it. Again, heat a long knife under hot tap water, dry it, and do your business.
Pieces can be any size you like. Here I’m dividing the cake into eight. As rich as this cake is, these pieces are huge. Ten would have been better, but oh well.
Now’s the time to put your opera cake in the refrigerator while you nip on down to the corner store for a little edible 23-karat gold.
Edible gold. You get it at the Quick Mart. Second shelf on the right next to the oatmeal. What sort of neighborhood do you live in? I’ll admit it’s tricky stuff to handle. You don’t want to touch it with your fingers, since it’ll stick and disintegrate when you try to peel it off. I use two x-acto knives as implements to cut and steady it, then just transfer pieces — of whatever shape — over to the cake. Not very elegant, but gold makes a statement whatever shape it’s in.
Your opera cake can now be refrigerated for a day or two if need be. Opera cake is best slightly chilled. Ideally not refrigerator-cold, maybe an hour or so out of the fridge. When you’re ready to serve, separate the pieces (again with a warm knife) and transfer to plates. Ah yes, the chocolate-on-the-bottom trick worked splendidly, did it not?
Thanks to Camille Malmquist for all the great advice, and to a very generous benefactor for the precious metal — and a terrific suggestion!