This is one of the most delicious opera cakes I’ve ever tried! Recently, I went to a birthday party at my friend Emma’s house and we really had an amazing time, everything was decorated in turquoise, so stylish, elegant, simply adorable…and a generous piece of the toffee opera cake with coffee and chocolate in the end – was totally a cherry on top! So, today am sharing with you this delicious toffee opera cake recipe that Emma found in the Gourmet Magazine.
For almond sponge cake:
- 2 whole large eggs at room temperature for 30 minutes
- 3 tablespoons cake flour (not self-rising), sifted after measuring, plus additional for dusting pan
- 1 cup almond flour (3 1/2 oz.) or 2/3 cup blanched whole almonds (see cooks’ note, below)
- 2 large egg whites at room temperature for 30 minutes
- ½ cup confectioners’ sugar, sifted after measuring
- 1/8 teaspoon salt
- 1/8 teaspoon cream of tartar
- 1 tablespoon granulated sugar
- 2 tablespoons unsalted butter, melted, foam discarded, and butter cooled
Toffee Syrup:
- ½ cup toffee syrup
For the coffee buttercream:
- 2 teaspoons instant espresso powder
- ¼ cup plus 1 tablespoon water
- 2 large egg yolks
- 1 stick (½ cup) unsalted butter, cut into ½ -inch cubes and softened
For chocolate buttercream:
- ¼ cup water
- 6 tablespoons granulated sugar
- 2 large egg yolks
- 1 stick (½ cup) unsalted butter, cut into ½ -inch cubes and softened
- 2 ounces melted semisweet chocolate
- 2 tsp dark cocoa powder
For chocolate glaze:
- ¾ stick (6 tablespoons) unsalted butter
- 7 oz fine-quality bittersweet chocolate (not unsweetened; preferably 70 to 71% cacao), coarsely chopped
- 1 cup toffee pieces, chopped finely
Special equipment: a 15- by 10-inch shallow baking pan; an offset metal spatula; a candy thermometer; a small sealable plastic bag.
Directions:
Make sponge cake:
- Put oven rack in middle position and preheat oven to 425°F. Butter baking pan, then lines bottom with a sheet of parchment or wax paper, leaving a 1-inch overhang on short sides, and generously butter paper. Dust pan with cake flour, knocking out excess.
- Beat whole eggs in a large bowl with a handheld electric mixer at high speed until eggs have tripled in volume and form a ribbon when beaters are lifted 2 to 3 minutes.
- Reduce speed to low, then add almond flour and confectioners’ sugar and mix until just combined. Resift cake flour over batter and gently fold in.
- Beat egg whites in a bowl with cleaned beaters at medium speed until foamy. Add cream of tartar and salt and beat until whites just hold soft peaks. Add granulated sugar, then increase speed to high and beat until whites just hold stiff peaks.
- Fold one-third of whites into almond mixture to lighten, then fold in remaining whites gently but thoroughly. Fold in butter, then pour batter evenly into baking pan, spreading gently and evenly with an offset spatula and being careful not to deflate (batter will be about 1/4 inch thick).
- Bake until very pale golden, 8 to 10 minutes, then cool in pan on a rack 10 minutes.
- Loosen edges of cake with a spatula, then transfer cake (on paper) to a cutting board. Cut cake into strips and squares. Trim outside edges slightly, then carefully peel paper from strips and squares and set back on paper.
Make coffee buttercream:
- Stir together espresso powder and 1 tablespoon water until powder is dissolved. Bring sugar and remaining 1/4 cup water to a boil in a very small heavy saucepan, stirring until sugar is dissolved. Boil, without stirring, washing down any sugar crystals on side of pan with a pastry brush dipped in cold water until syrup registers 238°F on thermometer (soft-ball stage; see cooks’ note, below).
- While syrup boils, beat yolks in a large bowl with cleaned beaters at medium speed 1 minute.
- Add hot syrup to yolks in a slow stream (try to avoid beaters and side of the bowl), beating, then add coffee mixture and beat until completely cool, 3 to 5 minutes. Beat in butter, 1 piece at a time, and beat until thickened and smooth.
Make chocolate buttercream:
- Bring sugar and remaining 1/4 cup water to a boil in a very small heavy saucepan, stirring until sugar is dissolved. Boil, without stirring, washing down any sugar crystals on side of pan with a pastry brush dipped in cold water until syrup registers 238°F on thermometer (soft-ball stage; see cooks’ note, below).
- While syrup boils, beat yolks in a large bowl with cleaned beaters at medium speed 1 minute.
- Add hot syrup to yolks in a slow stream (try to avoid beaters and side of the bowl), beating, then add coffee mixture and beat until completely cool, 3 to 5 minutes. Beat in butter, 1 piece at a time, and beat until thickened and smooth.
- Add chocolate and cocoa powder and mix until thoroughly incorporated.
Make glaze:
- Melt butter and all but 2 tablespoons chopped chocolate in a double boiler or in a metal bowl set over a saucepan of barely simmering water, stirring occasionally, until smooth.
- Remove top of double boiler and stir in remaining 2 tablespoons chocolate until smooth, then cool glaze until room temperature but still liquid.
Assemble cake:
- Put 1 cake square on a plate, then brush generously with one-third of toffee syrup. Spread half of buttercream evenly over top with cleaned offset spatula, spreading to edges.(Since I used two different types of buttercream. I layered coffee, chocolate, then coffee. Since you will have leftovers of each kind of buttercream, you can decide which buttercream you want to use the most of).
- Arrange both cake strips side by side on top of first layer (any seam will be hidden by next layer), then brush with half of remaining coffee syrup.
- Top with remaining cake square and brush with remaining coffee syrup. Spread remaining buttercream evenly over top, spreading just to edges. Chill cake until buttercream is firm, about 30 minutes.
- Reheat remaining glaze over barely simmering water just until shiny and spreadable (but not warm to the touch), about 1 minute. Pour all but 1 tablespoon glaze over the top layer of cake and spread evenly just to edges. Top with toffee pieces.
- Chill cake until glaze is set, about 30 minutes, then trim edges slightly with a sharp serrated knife.
Enjoy!
Bon Appétit!
