Opera Cake- France #118

Opera Cake- France #118

There are many stories about the origin of this cake. I'm going with this version---Pastry chef Dalloyau, of  a Parisian pastry shop, sold a dessert known as L'Opera, in honor of the Paris Opera. The cake is an almond sponge with a coating of coffee syrup. In between layers there is a coffee buttercream and chocolate glaze, which is also poured over the top.
Yields: 6-8 servings Total time: 3-1/2 hours, including chilling buttercream and glaze.

Almond Sponge Cake:

• 3 T. cake flour (not self-rising), sifted after measuring, plus additional for dusting pan
• 2 eggs at room temperature
• 1 c. almond flour 
• 1/2 confectioners' sugar, sifted after measuring
• 2 egg whites, at room temperature (save egg yolks for buttercream)
• 1/8 tsp. cram of tartar
• 1/8 tsp. salt
• 1 T granulated sugar
• 2 T. unsalted butter, melted, foam discarded, and cooled

Coffee Syrup:

• 1 tsp. instant-espresso powder
• 1/2 c. plus 1 T. water
• 1/2 c. granulated sugar
• 1/4 c. Cognac or other brandy

Coffee Buttercream:

• 2 tsp. instant-espresso powder
• 1/4 c. plus 1 T. water
• 6 T. granulated sugar
• 2 egg yolks
• 1 stick unsalted butter, cut into 1/2 inch cubes and softened

Chocolate Glaze:

• 6 T. unsalted butter
• 7 oz. fine-quality bittersweet chocolate (not unsweetened) coarsely chopped

1. Sponge Cake: Put oven rack in middle position and preheat oven to 425F.  Butter 15x10 baking pan, then line bottom with a sheet of parchment, leaving a 1" overhang on short sides, and generously butter paper. Dust pan with cake flour, knocking out excess.
2. 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, 2-3 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.
3. 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.
4. 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 off set spatula and being careful not to deflate (batter will be about 1/4" thick).
5. Bake until very pale golden, 8-10 minutes, then cool in pan on a rack 10 minutes.
6. Loosen edges of cake with 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.
7. Coffee Syrup:  Stir together espresso powder and 1 T. water until powder is dissolved.  Bring sugar and remaining 1/2 cup water to a boil in a 1-2 qt. heavy saucepan, stirring until sugar is dissolved.  Reduce heat and simmer syrup, without stirring, 5 minutes.  Remove from heat and stir in Cognac and coffee mixture.
8. Coffee Buttercream:  Stir together expresso powder and 1 T. water until powder is dissolved.  Bring sugar and remaining 1/4 c. 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 240F on thermometer (soft-ball).
9. While syrup boils, beat yolks in a large bowl with cleaned beaters at medium speed -1 minute.
10. Add hot syrup to yolks in a slow stream (try to avoid beaters and side of bowl), beating, then add coffee mixture and beat until completely cool, 3-5 minutes.  Beat in butter, 1 piece at a time, and beat until thickened and smooth.
11. Chocolate Glaze:  Melt butter and all but 2 T. chopped chocolate in a double boiler or in a mental bowl set over a saucepan of barely simmering water, stirring occasionally, until smooth.  Remove top of double boiler and stir in remaining 2 T. chocolate until smooth, then cool glaze until room temperature but still liquid.
12. Assemble Cake:  Put 1 cake square on a plate, then brush generously with 1/3 of coffee syrup.  Spread half of buttercream evenly over top with cleaned offset spatula, spreading to edges.
13. 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.  Spread half of glaze evenly over top, spreading just to edges.
14. 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.
15. 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 T. glaze over top layer of cake and spread evenly just to edges.  Scrape remaining tablespoon glaze into sealable plastic bag and twist bag so glaze is in 1 corner.  Snip a tiny hole in corner and decorate cake (leave a 1/2" border around edges).  Chill cake until glaze is set, about 30 minutes, then trim edges slightly with a sharp serrated knife. 

Results: I didn't have any almond flour, so I made it. Pulse whole blanched almonds with confectioners' sugar in a food processor until powdery.  Be careful not to grind to a paste. I think I cut the squares too large because I only ended up with 1 square and 2 strips. However, I stacked them and no one knew the difference. I also decorated the cake with pieces of orange and crumbled milk chocolate. The cake was absolutely delicious, especially served with espresso. It's not hard to make, just takes a lot of time. All tasters gave it a thumbs up.
Bottom Line: I might do it again because it was so good. However, it did take a lot of time.

Please share with Opera lovers around the world. Better yet, share with chocolate lovers. Another group to share with- coffee lovers. Thanks.