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Saturday, December 26, 2009

Chocolate Opera Cake for a Christmas Gift

A friend asked me to make an opera cake she could give as a Christmas gift and requested that I use the best chocolate, with 70% cacao. I got some Ghirardelli Extra Bitter Chocolate and some Scharffen berger semi-sweet and went to work. It was my Christmas Day project.

I thoroughly enjoyed myself making it except that it got off to a bad start as I used a genoise recipe that must have had a mistake in it - it produced layers that looked like tough pancakes; then I turned to Helen's (Tartlette's) recipe for genoise, which I had used before. It is a lovely recipe, producing a light, rich sheet of sponge cake. For the soaking syrup, I used Grand Marnier in the mix.

I chose Rose Levy Berenbaum's recipe for Chocolate Buttercream from her Cake Bible, and a chocolate glaze recipe from Carole Walter's Great Cakes. I topped the finished cake with white chocolate curls, made from Callabaut chocolate. I was pleased with the way my cake came out; however, the finishing is a bit wonky and the curls way too thick - just needs lots more practice, I guess.


Tartlette's Vanilla Genoise
3 large eggs
3 large egg yolks
1 teaspoon (4gr) vanilla extract (I used 1/2 teasp. vanilla and 1/2 teasp. almond essence)pinch of salt
¾ cup (150gr) of sugar
½ cup (70gr) cake flour
¼ cup (30gr) cornstarch

Preheat the oven to 400F and set a rack in the middle.Lightly spray a 12x17 baking sheet with cooking spray or lightly brush with melted butter. Set aside
Whisk the eggs, egg yolks, vanilla, salt and sugar together in a large bowl over a pan of simmering water. Whisk gently until the mixture is just lukewarm, about 100F on a candy thermometer(or test with your finger - it should be warm to the touch).
Transfer the mixture to the bowl of a stand mixer fitter with the whisk attachment (or hand held beaters) and whip on medium-high speed until the egg mixture is cooled and tripled in volume. The mixture will be thick and will form a slowly dissolving ribbon falling back onto the bowl when the whisk is lifted.
Over a medium bowl or a piece of parchment paper, sift together the flour and cornstarch.
Add one-third of the flour mixture to the beaten egg mixture. Use a rubber spatula to fold in the flour mixture, making sure to scrape all the way to the bottom of the bowl to prevent the flour mixture from making lumps. Repeat with another third of the flour mixture and finally with the remainder.
Pour the batter into the prepared pan and smooth the top with an offset spatula.
Bake the genoise for about 10 to 12 minutes. Make sure the cake does not over bake and become too dry or it will not roll properly. Let cool on a rack. Remove the cake from the baking sheet and invert it on a larger piece of parchment paper. Peel of the parchment paper that was lining the baking sheet. Set the cake aside.

Soaking Syrup
1/2 cup water
1/4 cup sugar
2 Tbs. Grand Marnier

Chocolate Buttercream (Rose Levy Berenbaum's Cake Bible)
9 ozs. bittersweet chocolate
4 sticks unsalted butter, softened
4 large egg whites
1 cup sugar

Break the chocolate into squares and place in a double boiler over very hot water or low heat. The water must not exceed 160 degrees F. or touch the bottom of the double boiler insert.
Remove double boiler from the heat and stir frequently until the chocolate begins to melt.
Return to the heat if the water cools, but be careful that it does not get too hot. Stir 8 to 10 minutes or until the chocolate is smooth. (Chocolate may be melted in microwave oven on high power if stirred every 15 seconds. Remove before fully melted and stir, using residual heat to complete the melting.)

In a mixing bowl beat the butter until smooth and creamy. (I used my KitchenAid and let it beat until the butter turned a pale cream color - about 5 mins.)

In another mixing bowl beat the egg whites until soft peaks form when the beater is raised. Gradually beat in the sugar until stiff peaks form when the beater is raised slowly. Beat in the butter by the tablespoon. If the mixture looks slightly curdles, increase the speed a little and beat until smooth before continuing to add more butter. Add the melted and cooked chocolate all at once and beat until smooth and uniform in color. Place in an airtight bowl. Re-beat to restore texture.

Carole Walter's Ganache Glaze from Great Cakes

Carole Walter's Ganache Glaze
Makes about 1 cup, enough to cover the top and sides of a 9 or 10 inch layer or tube cake

6 oz. (good) semisweet or bittersweet chocolate, like Lindt
6 oz. (¾ cup heavy cream
1 tbsp. light corn syrup
1 Tbsp. Grand Marnier, Cointreay, or dark Jamaican rum (optional)
¾ tsp. vanilla
½ - 1 tsp. hot water, if needed

Blend vanilla and liqueur/rum together and set aside.

Break the chocolate into 1-inch pieces and place in the basket of a food processor and pulse until finely chopped. Transfer into a medium sized bowl and set aside.

Heat the cream and corn syrup in a saucepan, on low, until it reached a gentle boil. Once to the gently boil, immediately and carefully pour over the chocolate. Leave it alone for one minute, then slowly stir and mix the chocolate and cream together until the chocolate is melted and incorporated into the cream. Carefully blend in vanilla mixture. If the surface seems oily, add ½ - 1 tsp hot water. The glaze will thicken, but should still be pourable. If it doesn’t thicken, refrigerate for about 5 minutes, but make sure it doesn’t get too cold!