Opera Cake, a Step-by-Step Guide

I gave myself a challenge last week.

When some departing coworkers requested a cake, I immediately thought of opera cake. To me, it's the epitome of French pastries - grand, complex, and decadent. As with many desserts, I had an idea what I wanted it to taste like, but I've never had a good one. In fact, I've only ever tasted one opera cake, at a culinary institute bakery in Vancouver, but I was sorely disappointed by the harsh sugary ganache and bone-dry sponge cake. Opera cake should be rich and complex, with each layer contributing both flavor and texture.

I. The Anatomy of Opera Cake (bottom up):

1. Almond Sponge (Jaconde): The sponge should be dry, so it can soak up liberal amounts of coffee syrup. Syrup drenched cake is luscious and moist and very, very delicious (it's my favorite part of the cake). The bottom piece of sponge is coated with melted chocolate on the bottom, to keep it from being soggy and to help hold up the cake.

2. Coffee Buttercream: The buttercream needs a strong coffee component to balance it's rich and creamy texture.
3. Almond Sponge.
4. Chocolate Ganache: The ganache should be melt-in-the-mouth creamy and taste like real chocolate.
5. Almond Sponge.
6. Chocolate Glaze: Personally I think the glaze should be made with unsweetened chocolate so it delivers a extra chocolate kick at the end. I never understood sugary glazes.

II. Assembly:
Components: 3 pieces sponge cake, coffee syrup, coffee buttercream, chocolate ganache, chocolate glaze. I used the recipe from Paris Sweets, except for the sponge cake, which I took from Indulge. 

1. Coat the bottom of one piece of sponge cake in chocolate (I made a big cake and a smaller practice cake). You'll want to coat the side that's less spongy, to save the spongy side for syrup love later.

2. Once the chocolate is dry, flip the piece over and soak it liberally in coffee syrup. As Claire Clark puts it, there should be no white sponge showing. She's the head pastry chef at The French Laundry, so I'd take her word for it (in fact, even though I thought I soaked the cake thoroughly, once I tasted the cake I wish I had put on more syrup).

3. Cover the cake with most of the coffee buttercream. Try to level it as best as you can.

4. Cover with another layer of sponge. Soak liberally with coffee syrup. Chill it in the fridge a bit to harden up.

5. Spread chocolate ganache on top, as level as possible. I found it useful to warm the ganache slightly so it's easier to work with.

6. Put the last layer of sponge cake on top. Soak with syrup, then spread a thin layer of remaining buttercream on top to create a smooth surface for the glaze. Chill again to harden.

7. Spread on the glaze. Try to get a level surface on top without working the glaze too many times (otherwise it loses its shine). I had a lot of trouble with this part, because I wanted it mirror smooth. Eventually I settled with "kind of flat". I found that if you heat the surface with a blow dryer, it'll melt the glaze on top and soften any hard edges on the surface of the glaze.

8. Wait until the glaze is set, then trim off the edges to make a neat rectangle/square (I settled for quadrilateral, I have trouble with right angles).

9. Snack judiciously on the trimmings. It may be tempting, but eating all of it will make you feel very, very sick.

10. Wrap the cake tightly in plastic wrap and store in the fridge until ready to serve. Let it come to room temperature (~ 1 hr) before serving. I found that the texture and taste of the cake improved after I let it sit for a day in the fridge.