Episode 9, GBBO 2013, Showstopper

Opera Cake

Marilyn

We may never know who invented that now-classic French gâteau, the opera cake. There are several claimants, including a legendary pastry chef in Paris, Louis Clichy, who supposedly premiered something like it at the Paris Exposition Culinaire in 1903. His creation was originally called the Clichy cake but was later renamed opera cake. The other person closely associated with the opera cake is Cyrique Gavillon, who worked at the Parisian pastry shop Dalloyau in the 1950s. According to the shop’s own website, Gavillon invented the cake in 1955, and his wife, Andrée Gavillon, compared it to the stage of the Opera Garnier in Paris. Thus it was named “the opera.” The only problem with these legends is that an ad for “gâteau opéra” appeared in the newspaper Le Gaulois on March 18, 1899.

While opera cake is traditionally made of thin layers of joconde sponge soaked with coffee syrup and sandwiched with buttercream and chocolate ganache, the brief for this challenge set before the bakers in the semifinals of The Great British Bake Off was to use any flavors they choose. Mary Berry was looking for “sheer perfection” in their cakes, with thin, even layers. Paul Hollywood said it was all about timing. Ruby’s was a chocolate, almond praline and saffron opera cake. Frances made a lemon sponge and lavender buttercream “soap opera” cake. Beca used the flavors of banoffee pie, and Kimberley combined the flavors of passionfruit and lime with dark chocolate.

The inspiration for my opera cake came from the popular ‘70s dessert, the Watergate cake, which may have been inspired by Watergate salad, although that could lead to an endless chicken-and-egg discussion. A recipe for the cake first appeared in a Maryland newspaper in September 1974, just a month after President Nixon resigned amid the Watergate scandal, but its popularity really took off a couple years later when Jell-O introduced its pistachio-flavored pudding. The cake, like the salad, featured the almost-iridescent-green pistachio pudding, chopped pecans, and sweetened coconut (for the cake) or pineapple (for the salad). (The cake recipe also used a white cake mix and a cup of 7-Up, like it needed more sugar!) 

My interpretation of the Watergate cake in operatic form was to make a pistachio joconde sponge brushed with a pistachio syrup and layer it with coconut Swiss meringue buttercream and pineapple filling studded with pecans. I finished it off with a thin chocolate glaze.

  • Joconde sponge brushed with pistachio syrup…
  • …layered with a coconut meringue buttercream…
  • …and pineapple filling studded with chopped pecans.

The pistachio joconde recipe came from the delightful blog of food stylist, photographer and trained pastry chef Aran Goyoaga, CannelleVanille.com, finalist for the 2012 and 2013 James Beard Award for Best Individual Food Blog.

For the pistachio syrup, I followed these directions for making pistachio orgeat (pronounced OR-zhot), which is a version of a cocktail syrup usually made with almonds, from Liquor.com. It was a pretty messy affair and yielded less than the promised 1¼ cups of syrup from 2 cups of pistachios, but the resulting dark green syrup did have a rich pistachio flavor that lent flavor and moistness to the sponge.

The coconut buttercream layer came from a coconut cake recipe on BrownEyedBaker.com. I have to admit this is the first time I’ve made a Swiss meringue buttercream, but her directions were simple enough they took away any first-time jitters I might have had. Because this one calls for 2/3 cup of coconut milk at the end, it’s not as stiff as some buttercreams, so I folded in some shredded coconut to give it more body.

I must confess that I cheated on the pineapple filling and used some that I froze after making my Banana Split Trifle earlier this year. I wasn’t sure how it would hold up after thawing because of the cornstarch used as a thickener, but once I reheated it on the stove to let the cornstarch re-dissolve, it tasted great and thickened up again nicely. Obviously this isn’t ideal, so make it fresh if at all possible.

The chocolate glaze came from this recipe. It’s thinner than a ganache, and I liked the fact that it uses vegetable oil rather than butter for a glossier finish.

I got feedback from several recipients of my Watergate Opera Cake. Although (sadly) none of them remembered ever having Watergate cake, they all enjoyed the combination of flavors and gave my opera cake a thumbs up!

Watergate Opera Cake

Pistachio orgeat credit: Liquor.com
Joconde sponge adapted from CannelleVanille.com
Coconut Swiss buttercream adapted from BrownEyedBaker.com
Pineapple filling credit: Food.com
Chocolate glaze credit: EvilTwin.kitchen

For the pistachio orgeat:

  • 2 c. raw, shelled pistachios
  • 1½ c. sugar
  • 1¼ c. water
  • ½ t. orange blossom water (optional)
  • 1 oz. (2 T.) vodka (optional)

    Directions

    1. Pulse pistachios in a food processor or blender until finely ground. Combine the sugar and water in a saucepan over medium heat and stir until sugar dissolves completely. Bring to a boil and boil the syrup for three minutes, then add the ground pistachios. Turn the heat down to low and simmer for another three minutes, then slowly increase the temperature to medium high. Just before it starts to boil, remove it from the heat and cover with a lid. Leave the covered nut mixture to infuse for 3-8 hours while you make the joconde sponge. Then strain it through two layers of cheesecloth into a bowl (You will need to squeeze it with your hands. It will be very messy.) Reserve the ground pistachios for another use.* Stir the orange flower water and vodka into the nutty syrup, if desired. (The vodka helps preserve it.) Leftovers can be refrigerated for up to two weeks.

      *I made a wonderful pistachio baklava with the ground pistachios, using this recipe from The New York Times: https://cooking.nytimes.com/recipes/1017925-pistachio-baklava. Because there was already some sugar in them, I reduced the amount of sugar syrup by one-third.

    For the pistachio joconde:

    • 1 c. + 2 T. finely chopped, raw pistachios
    • 1½ c. powdered sugar
    • 1 c. almond flour
    • 1/3 c. + 1 T. all-purpose flour
    • 5 large eggs
    • 6 large egg whites
    • 1/3 c. sugar
    • 2½ T. butter, melted and cooled

    Directions

    1. In a food processor, add the powdered sugar and almond flour to the finely chopped pistachios and process until a fine meal forms. Place this mixture into the bowl of an electric mixer fitted with a whisk attachment, and add the flour and the whole eggs. Whip the mixture until a thick ribbon forms when the whisk is lifted out of the bowl, about 5 minutes. Transfer the mixture to a large bowl, and wash the mixer bowl and whisk attachment.
    2. Put the egg whites in the mixer bowl and whisk until a light meringue starts to form. Slowly sprinkle in the sugar and continue whisking until semi-stiff peaks form. Mix a third of the meringue into the first mixture, then gently fold in the rest of the meringue. Fold in the melted butter until it is all incorporated.
    3. Divide the batter into two 10-by-15-inch jellyroll pans and spread it evenly. Bake at 375°F for about 12 minutes or until it starts to turn a light golden color on top. Don’t let it get too dark. Remove from oven and turn out onto cooling racks. Cool completely before assembling, or store in refrigerator or freezer until ready to assemble.

    For the coconut Swiss buttercream:

    • 1½ c. sugar
    • 6 egg whites
    • 1 ½ c. unsalted butter, at room temperature and cut into 2-inch pieces
    • 1 t. coconut extract
    • ¼ t. kosher salt
    • 2/3 c. coconut milk
    • 1/2 c. shredded coconut

      Directions

      1. In a small, heatproof bowl, whisk together the sugar and egg whites. Place the bowl on top of a saucepan containing about an inch of simmering water. (The bottom of the bowl should not touch the water). Heat the mixture, whisking occasionally, for 6 to 8 minutes, or until the mixture is hot to the touch and the sugar is dissolved.
      2. Remove the bowl from the heat and transfer the mixture into the bowl of an electric mixer. Using the whisk attachment, whip on medium-high speed for 6 to 8 minutes, or until the mixture becomes a light, white meringue and is cool to the touch. Reduce the speed to low and add the butter, a couple of pieces at a time. Increase the speed to medium and mix for 4-5 minutes or until the butter is thoroughly incorporated and the buttercream is smooth and glossy. The buttercream may initially look curdled after adding the butter, but continue beating and it will come together, looking smooth and creamy by the end of the mixing time.
      3. Add the coconut extract, salt and coconut milk, and whip for another few minutes on medium speed or until the coconut milk is thoroughly incorporated and the buttercream is smooth. Again, it may look thin and separated, but continue mixing until it comes together. Fold in shredded coconut.

        NOTE: Use the buttercream within 30 minutes or transfer to an airtight container and store at room temperature for up to one day, then beat with a mixer (using the paddle attachment) until smooth before using. You can store leftover frosting in an airtight container in the refrigerator for up to two weeks, then bring to room temperature and beat with a mixer (using the paddle attachment) for 6-8 minutes until smooth before using.

      For the pineapple filling:

      • 3 T. cornstarch
      • ½ c. + 1 T. sugar
      • ½ t. salt
      • 20 oz. can crushed pineapple in juice
      • 3 T. butter

        Directions

        1. In a heavy saucepan, combine cornstarch, sugar and salt. Add pineapple with juice and mix well. Cook over medium heat, stirring constantly, until mixture comes to a bubbling boil. Once it comes to a boil, continue stirring constantly for about 5 more minutes, or until it’s thickened and loses its milky look. Remove from heat and add butter, stirring till melted. Let cool, then store in refrigerator until ready to use.

          NOTE: This makes more than you will need. You could halve the recipe if you want.

        For assembly and chocolate glaze:

        • ¼ c. chopped pecans
        • 1 c. (5.3 oz.) finely chopped dark chocolate, plus a little extra for decorating
        • 1/3 c. (1.7 oz.) finely chopped milk chocolate
        • 3 T. neutral tasting vegetable oil (I used canola)

          Directions

          1. Cut both cakes in half. Wrap one half in plastic and store in refrigerator for another use. Place another half on a parchment paper–lined serving plate or board. With a pastry brush, brush the cake with the pistachio orgeat syrup.
          2. Use an offset spatula to spread a layer of buttercream on top of the cake, about ¼-inch thick, or the same thickness as the cake. Make it as even as possible. Top with another layer of cake, and brush that with syrup as well.
          3. Spread that cake with pineapple filling, again about the same thickness as the cake, or ¼ inch. Sprinkle the pecans over the pineapple and top with the third cake layer. Press down on the top layer to make it as flat as possible, then brush with syrup again. Top that layer with more buttercream and spread as evenly as possible. Refrigerate the cake while you make the chocolate glaze.
          4. Combine the two kinds of chocolate and oil in a microwaveable bowl and heat in the microwave at 50% power for 1 minute. Stir well and heat again for 30 seconds at 50% power, then stir until chocolate is completely melted, repeating 30-second intervals and stirring well, as needed. Don’t let the chocolate overheat or burn
          5. Remove cake from refrigerator. If buttercream isn’t completely smooth, take a clean offset spatula, dip it in hot water, wipe it dry and then use it to smooth the hardened buttercream, wiping off excess buttercream onto a paper towel or the edge of a plate. Keep dipping, drying and smoothing as needed to create a smoother surface.
          6. Slowly pour the chocolate glaze over the cake, doing your best to cover the entire surface. It’s okay if it drips over the sides because they will be trimmed off anyway. It’s best if you can cover the top of the cake without spreading, but if you need to, use a clean offset spatula to spread the glaze all the way to the edges. Smooth it out as best you can.
          7. Refrigerate the cake for at least an hour. Before serving, remove cake from fridge, heat a long knife under hot water, then wipe it dry, and cut off the edges on all four sides of the cake, keeping the edges as straight and even as possible, wiping the knife on a paper towel between cuts and reheating with water, then drying on a towel, if needed.
          8. Trim the parchment paper to the edge of the cake, or transfer the whole thing to a clean cake board. Melt a little dark chocolate in the microwave and put it in a small piping bag fitted with a fine plain tip, or a zip-lock bag with a small hole cut out of one corner. Pipe the word “Opera” onto the top of the cake. (I also used a stencil and sprinkled some finely ground coconut on top, but that is purely optional.)
          9. Let the cake sit at room temperature for at least an hour before serving. If you’re serving it the same day, you can keep it uncovered in the refrigerator, but bring it to room temperature before serving so the buttercream will be nice and soft. Cover and refrigerate any leftovers.

          Next week: A Savory Picnic Pie

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