I think the Opéra cake is becoming one of my favorite styles of cake for its elegant style and limitless layering opportunities. I made this matcha Opéra cake for a recent birthday in my family. With its green tea joconde soaked in green tea syrup, green tea buttercream, black sesame seed chocolate ganache and chocolate glaze, it’s a must for green tea lovers!
For the joconde (and for most of the cake components for that matter), I used the Opera recipe from Dorie Greenspan’s Paris Sweets, and the May 08′s Daring Baker’s Challenge, adding some green tea powder. I also added black sesame seeds to give the ganache and cake a hint of a crunch. The top is sprinkled with confectioner’s sugar and green tea powder.
For the Joconde (edited from the May 08 Daring Baker’s challeng/Dorie Greenspan):
6 large egg whites, at room temperature
2 tbsp. (30 grams) granulated sugar
2 cups (225 grams) almond meal
2 cups icing sugar, sifted
6 large eggs
½ cup (70 grams) all-purpose flour
1 tbsp matcha green tea powder
3 tbsp. (1½ ounces; 45 grams) unsalted butter, melted and cooled
Divide the oven into thirds by positioning a rack in the upper third of the oven and the lower third of the oven.
Preheat the oven to 425◦F. (220◦C).
Line two 12½ x 15½- inch (31 x 39-cm) jelly-roll pans with parchment paper and brush with melted butter.
Beat the egg whites in a large bowl until they form soft peaks using stand mixer or handheld mixer. Add the granulated sugar and beat until the peaks are stiff and glossy.
Attach the paddle attachment to a stand mixer (or using a handheld mixer again) and using a separate bowl, beat the almonds, icing sugar, matcha powder and eggs on medium speed until light and voluminous, about 3 minutes.
Add the flour and beat on low speed until the flour is just combined. Do not overmix. It should only take a few seconds.
Using a rubber spatula, gently fold the meringue into the almond mixture and then fold in the melted butter. Again, avoid overmixing and deflating the batter. Divide the batter between the pans and spread it evenly to cover the entire surface of each pan.
Bake the cake layers until they are lightly browned and just springy to the touch. This could take anywhere from 5 to 9 minutes depending on your oven. Place one jelly-roll pan in the middle of the oven and the second jelly-roll pan in the bottom third of the oven.
Put the pans on a heatproof counter and run a sharp knife along the edges of the cake to loosen it from the pan. Cover each with a sheet of parchment or wax paper, turn the pans over, and unmold.
Carefully peel away the parchment, then turn the parchment over and use it to cover the cakes. Let the cakes cool to room temperature.
Green Tea Syrup:
2/3 cup water
3 tbsp granulated sugar
1 tbsp green tea powder
In a saucepan, heat water and sugar until boiling and sugar is dissolved. Take pan off the heat, let cool 2 or 3 minutes and add green tea powder, stirring. Let cool completely until ready to use.
Black Sesame Seed Ganache:
8 oz finely chopped bittersweet chocolate
1/2 cup whole milk
1/4 cup heavy cream
4 tbsp unsalted butter at room temperature
2 tbsp black sesame seeds coated in 1 tsp corn syrup
Place chopped chocolate in a medium bowl. Heat milk and cream in a saucepan until boiling. Pour the liquid over the chocolate, letting sit for 30 seconds before stirring slowly. Whip the butter and add to the melted chocolate in 2 or 3 additions. Stir in black sesame seeds. Let the ganache cool in the refrigerator, checking and stirring every so often. This ganache can be prepared several days in advance.
Green Tea Buttercream:
2 egg whites
1/2 cup sugar
pinch of salt
2 sticks unsalted butter, cut into tablespoon size chunks
Put the sugar and egg whites in a mixer bowl or another large heatproof bowl, fit the bowl over a plan of simmering water and whisk constantly, keeping the mixture over the heat, until it feels hot to the touch, about 3 minutes. The sugar should be dissolved. Remove the bowl from the heat.
Working with the whisk attachment or with a hand mixer, beat the meringue on medium speed until it is cool, about 5 minutes. Switch to the paddle attachment if you have one, and add the butter a piece at a time, beating until smooth.
Once all the butter is in, beat in the buttercream on medium-high speed until it is thick and very smooth, about 5 minutes. During this time the buttercream may curdle or separate – just keep beating and it will come together again. The buttercream can be prepared 2 days in advance.
1 stick unsalted butter
5 oz finely chopped bittersweet chocolate
To clarify butter, melt it in a saucepan. Scoop off the white froth that rises to the top and discard. Melt chocolate in a double boiler or in a bowl set over a pan of simmering water, being very careful not to get any water in the chocolate. Pour butter into the chocolate, avoiding the layer of milky residue that forms on the bottom.
Assembling the Cake:
The finished cake should be served slightly chilled. It can be kept in the refrigerator for up to 1 day.
Line a baking sheet with parchment or wax paper.
Cut a 10″ x 10″ square from each of the 2 sheet cakes. You will have two 5″ x 10″ pieces of cake left which will be laid side by side to form a third layer.
Place one square of cake on the baking sheet and moisten it gently with 1/3 of the green tea syrup. Spread about two-thirds of the buttercream over this layer.
Top with the two rectangular pieces of cake, placing them side by side to form a square. Moisten these pieces with another 1/3 of the syrup. Spread ganache over the second layer. Top with third square of joconde. Moisten with the last 1/3 syrup. Spread remaining 1/3 of the buttercream. Refrigerate (or freeze) until very firm.
Make the glaze and after it has cooled, pour/spread it over the top of the chilled cake, using an offset spatula to coax the glaze to the edges. Refrigerate (or freeze) the cake again to set the glaze.
Using a knife dipped in hot water and water wiped off with towel, trim the edges. Heat the knife/wipe clean with each slicing of cake.
Serve the cake slightly chilled. This recipe will yield approximately 20 servings.