It has chocolate frosting and chocolate mousse. Good. What is different about this cake? At first, I thought it's going to be a chocolate genoise base and started to get the ingredients ready. But I was wrong. It was a vanilla genoise base. I've never layered a vanilla genoise base or butter cake with chocolate frosting. Okay. Let's get going.
I've never tried Pierre Herme's genoise cake recipe before. I've been using Rose Levy Beranbaum's recipe. There's only very slight difference in 2 of the ingredients used. Pierre Herme uses melted butter and all purpose flour wheras Rose uses clarified butter and half cake flour and half corn flour respectively. What's the verdict? I still prefer Rose's recipe. It's lighter and more fragrant due to the use of clarified butter and cake flour combination. I'll post both Pierre's and Rose's recipe here and you can try them out and decide for yourself.
The next component I work on is the chocolate mousse. Again, this is the first time I use this chocolate mousse recipe and technique. The one that I tried did not use any egg yolk, just chocolate and heavy cream and a little gelatine. This one uses egg and we have to be extremely hygienic when preparing this 'cause the egg is not going to be cooked. We do not want to get salmonella poisoning. No gelatine is used here. Egg yolk is the 'glue' here to give the mousse structure. You can see the genoise and mousse in the picture below before I covered it with chocolate frosting.
(A) Genoise (Pierre Hereme's recipe)
38g unsalted butter
4 large eggs
102g plain flour, sifted
(A) Genoise (Rose Levy Beranbaum's recipe)
28g clarified butter
3/4 tsp vanilla essence
3 large eggs
37.5g cake flour
37.5g corn flour
94g ground-for-espresso coffee (coffee must be finely ground)
1/4 + 1/8 tsp instant coffee
(C) The Mousse
203g heavy cream
1 large egg, at room temperature
2 large egg yolks, at room temperature
142g bittersweet chocolate (preferably Valrhona Manjari), coarsely chopped
1.5 tbsp water
(D) The Almonds
3/4 cup sliced blanched almonds
1/4 tsp dutch-processed cocoa
1 tbsp reserved simple syrup
(E) The ganache
298g bittersweet chocolate (preferably Valrhona Noir Gastronomie), finely chopped
1 tbsp dutch-processed cocoa powder
145g heavy cream
- Centre a rack in the oven and preheat the oven to 350°F.
- Butter a 6" round pan, dust the interior with flour and tap out the excess.
- Melt the butter over a pot of simmering water. Set aside to cool. It should be just warm when ready to us
- Whisk the eggs and sugar together in a mixer bowl. Place the bowl over a pot of simmering water and whisk non-stop, until mixture is foamy, slighty pale, and between 130°F and 140°F, as measured on an instant-read thermometer, about 4 minutes. Remove the bowl from pot. Working in the mixer with the whisk attachment, beat the mixture on high speed until it cools to room temperature and triples in volume, about 5 to 8 minutes. You'll know it's just right if when you lift the whisk, the batter falls back into the bowl and forms a ribbon that remains on the surface for 10 seconds before it dissolves.
- Stir about 2 tablespoons of batter into the slightly cooled butter and set aside. Now, working with a large flexible rubber spatula, gently fold the flour into the batter in two or three additions (you might find it most convenient to add the flour to the bowl by shaking it through a strainer), taking care to handle the batter gently on order to maintain its bubble structure. (The batter will lose volume as you fold in the flour and later the butter. This reaction is inevitable and shouldn't jeopardize the success of the finished cake, but be careful just the same.) Still working with the spatula, fold in the butter mixture. At this point, the batter must be used immediately.
- Pour the batter into the prepared pan and bake for 28 to 33 minutes or until the top is golden and springy to the touch and a toothpick inserted into the centre of the cake comes out clean.
- Transfer the cake to a cooling rack, then unmould after 5 minutes. Turn the cake right side up to cool to room temperature on the rack.
- Stir the sugar and 94g water together in a heavy-bottomed saucepan. Bring to a boil over medium heat. As soon as the syrup comes to a boil, remove it from the heat. Cool to room temperature.
- Spoon off two tablespoons of the simple syrup, cover, and refrigerate to use for the glazed almonds. Keep the remainder of the syrup at the ready. Line a strainer with a double thickness of dampened cheesecloth and place it over a small bowl; keep close at hand.
- Bring the 320ml water to the boil in a medium saucepan. Add the coffee, stir and immediately pour the mixture through the lined strainer. You should have about slightly less than 3/4 cup of very dark coffee. Stir in the instant coffee and the simple syrup. Set the syrup aside until needed. (The syrup can be made up to a week ahead and kept covered in the refrigerator.)
(C) The Mousse
- Beat the cream until it holds medium-firm peaks, then cover and chill it until needed. Place the eggs and yolks in the bowl of a mixer fitted with the whisk attachment and beat the lowest speed for a few seconds, just to break up the eggs; set them aside while you prepare the chocolate and sugar syrup.
- Melt the chocolate in a microwave oven or in a metal bowl over a pan of simmering water. Remove the chocolate from the heat and, if necessary, pour it into a bowl large enough to hold all the ingredients for the mousse. Cool the chocolate to 114°F, as measured on an instant-read thermometer.
- While the chocolate is melting and cooling, place the sugar and water in a small heavy-bottomed saucepan. Bring the mixture to a boil, stirring occasionally and washing down the sides of the pan with a pastry brush dipped in cold water. Boil the syrup over high heat without stirring it until it reaches 257°F, as measured on an instant-read thermometer, about 8 to 10 minutes, then immediately remove it from the heat.
- With the mixer on the lowest speed, beat the eggs for a few seconds, then very slowly, add the hot sugar syrup in a thin, steady stream. To avoid splatters, try to pour the syrup down the side of the bowl, not into the spinning whisk. (Inevitably, some will splatter, but don't attempt to scrape the hardened syrup into the eggs - you'll get lumps.) Increase the mixer speed to high and beat the eggs for about 5 minutes, or until they are pale and more than double their original volume. If the mixture is still warm, reduce the speed to medium and continue to beat until the eggs are at room temperature.
- Using a large rubber spatula, fold about one quarter of the whipped cream into the chocolate. Fold in the rest of the cream and then, very delicately, fold in the whipped egg mixture.
(D) The almonds
- Centre a rack in the oven and preheat the oven to 325°F. Toss the almonds with the cocoa, then toss with the syrup to coat, and spread them out on a parchment-lined baking sheet. Toast the almonds, stirring every 3 to 4 minutes, until they are deeply and evenly browned, about 10 to 12 minutes. Transfer the sheet to a rack and cool the almonds to room temperature. (The almonds can be used immediately or packed into an airtight container and stored at room temperature for about 4 days.)
- Centre a 6" dessert ring on a cardboard cake round. Place one layer of genoise, cut side up, in the ring. Brush enough coffee syrup over the cake to moisten it thoroughly.
- Using an offset spatula or flexible rubber spatula, spread about 1½ - 1¾ cups of mousse over the cake and smooth the top.
- Position a second layer of the cake over the mousse and spread another 1½ -1¾ cups of mousse over the cake and smooth the top level with the edge of the dessert ring.
- Transfer the cake to a freezer and freeze for 2 hours to set the mousse.
(E) The Ganache
- Place the chocolate and cocoa in a medium bowl.
- Bring the cream to a boil and remove it from the heat. Pour the cream into the chocolate in three additions, using a rubber spatula to stir the mixture in concentric circle, starting each time with a small circle in the centre of the bowl and working your way out into larger circles. You'll have a smooth, glossy ganache.
- Allow the ganache to rest uncovered and undisturbed (don't stir it) at room temperature until it sets, 40 to 60 minutes, depending on the room temperature. When the ganache is properly set, it will hold a ribbon for a second or two when stirred. It is ready to be used now or covered and refrigerated until needed. If ganache is chilled, it must be brought back to its consistency by leaving it a room temperature until it's spreadable (the best method), or by heating it over hot water or in a microwave oven at low power. Do nit beat it or otherwise overwork it, or it will lose its lovely - and charateristic - sheen.
- When the ganache is setting up, transfer the cake from the refrigerator to the counter. (Working on a cold rather than a solidly frozen cake will facilitate applying the ganache.)
- Remove the dessert ring. Using a long metal offset spatula, spread ganache over the top and sides of the cake. If you need to repeat with another one or two layers of ganache, go ahead - you've got plenty of ganache to play with. If the ganache is set enough to hold a design, you can decorate the top now. If the ganache is still very soft, return the cake to the refrigerator for a few minutes to set it enough to hold a line drawn across its surface with a knife. (keep the leftover ganache at hand so you can cover uo any design attempts that don't pass muster.)
- Decorate the top of the cake using the blade of a long serrated knife, such as a bread knife. Hold the handle of the knife with one hand and the tip with the other. Starting at one edge of the cake and holding the knife almost perpendicular to the cake, gently slide the knife from one edge to the other. Without "losing your place" at the edge of the cake, shift the blade about 1/16 inch and slide it back to the opposite edge of the cake. You will have created the first V in a herringbone pattern. Continue until you have decorated the entire top of the cake. If the knife blade becomes clogged with ganache, clean the blade before continuing the pattern. Return the cake to the refrigerator for a few minutes to set the design.
- The last step is to press the toasted almonds against the sides of the cake. The cake can be served now or chilled until serving time.