Opera Cake: Step by Step

I wanted to make a fancy coffee-chocolate dessert for a dinner party and didn't have any luck finding Chocolate Desserts by Pierre Hermé in several bookstores. In the end, I decided on the classic Opera Cake using the detailed recipe here.

The cake layers are based on a recipe that has ground almonds. I overbeat the egg whites somewhat so that they became grainy and difficult to smoothly incorporate into the batter. You can see a few specks of egg white in the photo. I rotated the pans top to bottom during baking, and needed almost double the time to get the cake lightly browned. The directions for cooling are unnecessarily complicated so I just let them cool right in the pan.

 

Even though the cake layers have a lot of structure from the egg whites, they're still very delicate. Such a large sheet is prone to cracking when you pick it up, so be gentle. I placed the bottom layer on a piece of wax paper on top of an inverted sheet pan (so that I would be able to easily move it). There is a lot of coffee syrup so I was generous with brushing it on.

 

I made a buttercream recently so had a bit of experience to draw on. This one had yolks in it and far fewer egg whites and the quantity was smaller. When it was done, I popped the mixer bowl into the fridge for five minutes at a time, then whipped it for 10 seconds. Once it was firm enough to be easily spreadable, I gently scraped it into a bowl, avoiding the crystallized sugar on the sides of the bowl. Next time, I'll chill it for less time, since it was tricky to spread it evenly without damaging the cake.

 

For the chocolate ganache, I made use of the microwave to heat the small quantity of milk and cream. I also didn't bother to beat the butter, as it was very soft already. After I chilled the ganache in the fridge for a bit, I let it sit at room temperature while I worked on the bottom layers. Unfortunately, the ganache started to set, so I needed a brief amount of time over a double boiler to make it spreadable again.

 

After assembling the cake layers, I let it chill in the fridge for about 5 hours. The glaze has a lot of clarified butter, so I made sure to stir it thoroughly. You have to work quickly with the glaze as it starts to set on the cold cake immediately. I didn't use an offset spatula to smooth the top, choosing to fix gaps with a spoon and ended up with an amateurish surface.

 

The classic decoration is edible gold leaf and the name of the cake piped in melted chocolate. In keeping with the musical name, I piped treble clefs in tempered white chocolate, and also tried several variations of writing the word Opera. I chilled the pieces as the small decorations got soft quite quickly.

 

The layers are relatively even so I was pretty pleased. The cake is very easy to cut with a sharp knife. To keep the edges from drying out, I tried to cover them with strips of acetate but the natural curl in the plastic made it difficult to adhere securely.

 

The finished cake. I cut it into twenty 2×2½" pieces. I agree with Clement that it's better served at room temperature or warmer as the buttercream and ganache are too firm otherwise. The flavours are well-balanced and combine into a wonderful dessert. Highly recommended!