Opera Cake
Ingredients:
Almond sponge cake
- 6 large egg whites, room temperature
- 20 grams granulated sugar
- 300 grams ground blanched almonds
- 400 grams confectioners' sugar, sifted
- 6 large eggs
- 75 grams all-purpose flour
- 20 grams butter, melted and cooled
Espresso syrup
- 1/2 cup water
- 1/3 cup sugar
- 3 tablespoons strong espresso
Coffee buttercream
- 2 tablespoons strong espresso
- 2 tablespoons boiling water
- 200 grams sugar
- 20 ml water
- 1 teaspoon vanilla extract
- 1 egg
- 1 egg yolk
- 80 grams butter, at room temperature
Dark chocolate ganache
- 200 grams bittersweet chocolate, finely chopped
- 125 ml whole milk
- 60 ml heavy cream
- 20 grams butter, at room temperature
Chocolate glaze
- 150 grams bittersweet chocolate, finely chopped
- 125 grams butter
Method:
To make the almond sponge cake
- Preheat the oven to 190C. Line two 15-inch by 12-inch pans with parchment paper and brush the surface of the paper with butter. Set them aside for a moment.
- Using an electric beater, beat the egg white on high until they become foamy and start to expand.
- Sprinkle in the sugar, one teaspoon at a time, until all of it if incorporated into the egg whites. Continue beating the meringue until it is glossy and holds stiff peaks.
- In a separate bowl, beat the ground almonds, confectioners' sugar, and whole eggs on medium just until the mixture becomes light and foamy.
- Gently stir the flour into the almond batter.
- Gently stir 1/4 of the almond batter into the whipped egg whites.
- Fold the remainder of the almond batter and the melted, cooled butter into the egg whites.
- Divide the sponge cake batter between the two prepared pans and bake the cakes for 5 minutes, until the surfaces spring back from a light touch.
- Cover the top surface of each cake with a fresh piece of parchment and carefully invert them onto a clean surface.
- Slowly peel back the old parchment from the cakes and allow them to rest loosely over the cakes to prevent them from drying out.
To make the espresso syrup
- In a small saucepan, set over medium heat, bring 1/2 cup water, 1/3 cup granulated sugar, and 3 tablespoons espresso to a boil.
- Allow the mixture to cool for 5 minutes.
- Set it aside to brush onto the cake later.
To make the coffee buttercream
- Stir together the espresso and boiling water and set the mixture aside for a moment. In a medium saucepan, set over medium heat, bring 1 cup sugar, 3 tablespoons water, and 1 teaspoon vanilla extract to a boil.
- Continue cooking it until it reaches 120C on a candy thermometer.
- Remove the sugar syrup from the heat and allow it to cool slightly.
- In a separate bowl, beat the egg and egg yolk until they begin to get fluffy.
- Continue to beat the mixture and add the hot sugar syrup to the bowl in a smooth, steady, slow stream.
- Once the syrup is incorporated, mix in the reserved coffee mixture.
- Continuing to beat on medium-high, add the butter, one tablespoon at a time, until it is fully incorporated into the buttercream.
- The coffee buttercream is completely once it turns thick and fluffy.
To make the ganache
- In a medium saucepan, set over medium heat, bring the milk and cream to a boil.
- Remove the pan from the heat and stir in the chocolate.
- Continue stirring the chocolate for 2 minutes, to insure a completely smooth texture.
- Stir in the butter and continue stirring the ganache for 90 seconds.
To assemble the cake
- Line a large baking sheet with parchment paper.
- Cut one 10-inch by 10-inch square out of each layer of cake and place it on the baking sheet.
- Brush the cake with the espresso syrup. Carefully spread 3/4 of the coffee buttercream over the surface of the cake.
- Place the two spare rectangles of cake over the buttercream, and then brush them with espresso syrup.
- Spread the ganache over the cake in a smooth layer.
- Place the last layer of cake over the ganache, brush with espresso syrup, and then spread it with a thin layer of the coffee buttercream.
- Chill the cake in the refrigerator for 1 hour before glazing it.
To glaze the cake
- Clarify the butter by boiling it, skimming off, and discarding the solids.
- Melt the chocolate in a double boiler and stir in the clarified butter until the glaze is smooth.
- Pour the chocolate glaze over the cake and allow it to set in the refrigerator before serving