Because I didn't have enough fun making an opera cake for Daring Bakers, I went for another layered, multi-component cake last week. Sometimes I like to go for simple, breezy creations and other times I just feel like challenging my skills. Making layer cakes is always an exercise that keeps me on my pastry toes. Also, it was my sister's birthday, and she is an unabashed lover of all things chocolate. I'd had my eye on this elegant little number from Pichet Ong's The Sweet Spot for quite a while, and now seemed like the ideal time to break it out.
As Ong describes his creation, it's a death by chocolate cake filtered through a distinctly Asian sensibility. Unlike most Western odes to decadence, which usually involve adjectives like fudgy, gooey, or sticky, and accoutrements like nuts, whipped cream and a cherry on top, this dessert hews to a lighter, more ethereal course. But I'm happy to say the perfect balance of flavors and textures makes it no less dreamily satisfying.
Besides a tendency towards airier, more restrained composition, I've also noticed that many Asian desserts have an affinity for pairing chocolate with malt or coffee. Ong goes for the triple play by combining a chocolate genoise with a malted chocolate mousse and a Vietnamese coffee buttercream. I made all three components, but when it came to assembling them I found I preferred the way the cakes looked without the buttercream. The original recipe called for making one big square cake, which is naturally easier to frost than several small round cakes. The smoky-sweet buttercream, made with Vietnamese coffee and condensed milk, was definitely spoon-licking good though, and I'll probably find a way to use it again, whether in this dessert or another.
My aim was to make those elegant individually-sized cakes you see in those French patisseries, and to make them you need those little metal cake rings. Using them is a bit like making a cake with a blindfold, since you can't see whether your layers are even. It was even trickier with this dessert since it was designed to make a single cake, and I didn't know whether the amounts of cake and mousse were proportioned to making multiple miniature cakes. A little eyeballing, a little guestimating, and I came out with some fairly well-stacked little guys. If it's any reassurance, though, even if the cakes don't come out perfectly even (and I had a few) they're still just as delicious!
The cake is basically a cocoa-flavored genoise and bakes up like a dream: light, springy, and moist. The malted chocolate mousse is airy, creamy, and silky, like all the best mousses should be. I never knew that malted milk was so popular around the world until I went to Hong Kong when I was ten and saw ads on tv touting Horlicks as the perfect breakfast food. In the United States, Carnation and Ovaltine are the most popular brands, but elsewhere there several other choices, the most well known ones being Horlicks and Milo. The same brands can be formulated differently for different markets, so be sure to compare and find which one you like best. Many brands, like Ovaltine and Milo, have cocoa in them so they have a sweeter, more chocolatey flavor. Horlicks has the most straightforward, unsweetened malt flavor. Ong recommends Horlicks in his recipe; combined with bittersweet chocolate it makes for a lovely mousse with notes of caramel and cocoa. I'm not sure if I use quite enough gelatin in making the mousse: it was wonderfully smooth and creamy but was not as firm as I would have liked. I think I might recommend against adding more gelatin and just noting that these cakes will soften up quite quickly once you remove them from the refrigerator.
Dusted with a little cocoa on top, this cake reminds of Maltesers, another malted delight I was introduced to in Hong Kong. I consumed these malted milk balls by the bagful whenever I went there. There is a brand of malted milk balls in the US called Whoppers but to me there is absolutely no contest: Maltesers are far and away the superior candy. When a dessert makes me think of malted milk balls, I know it's going to stay on my list of favorites. It might take a bit of time in the kitchen, the results are surely worth it: an ideal chocolate indulgence for springtime.
Malted Chocolate Mousse Cakes
adapted from Pichet Ong's The Sweet Spot
Makes about 8 2 1/2" round cakes
1/2 cup plus 2 tablespoons (45 g) cocoa powder
3 tablespoons flour
2 tablespoons cornstarch
5 large eggs, separated
2/3 cup (125 g) sugar
4 large egg yolks
1 teaspoon salt
1/4 up (50 g) vegetable or canola oil
3 tablespoons buttermilk
Malted Chocolate Mousse
3/4 cup (168 g) whole milk
1/2 cup (98 g) sugar
1/4 teaspoon salt
1/4 cup (37 g) malted milk powder
6 large egg yolks
1 1/4 teaspoons powdered gelatin, dissolved in 1 tablespoon cold water
5 ounces (150 g) bittersweet chocolate, roughly chopped
1 cup (226 g) whipping cream
To make the cake: Preheat the oven to 350 degrees F. Spray an 11 x 17 baking pan with cooking spray, line with parchment paper, and spray again. If you can find a pan with a rim at least 1" high, that's probably best – some jelly roll pans might a little too shallow.
Sift the cocoa, flour, and cornstarch into a bowl and set aside.
In stand mixer with the whisk attachment, whisk the egg whites at medium-high speed until soft peaks star to form. Add 1/3 cup of the sugar in a slow, steady stream. Continue whisking medium-soft peaks have formed. Do not overwhip the whites. Scrape the whites into a bowl, and clean the mixer bowl and whisk.
Place all 9 egg yolks in the clean mixer bowl and whisk on medium until they are combined. Add the salt and remaining sugar in a slow, steady stream. Continue whisking until the mixture is pale yellow and very thick.
Whisk about half of the egg whites into th e egg yolk mixture by hand to lighten it up. Fold in the dry ingredients carefully until almost fully incorporated. Fold in the rest of the egg whites carefully.
Whisk the oil and buttermilk together in a bowl. Fold into the batter until fully incorporated.
Spread the batter into the pan and even out the surface with an offset spatula. Bake for 10 minutes, rotating halfway through. The surface should be just dry and springy to the touch. Let cake cool on rack.
To make the mousse, combine the milk, sugar, and salt in a small saucepan. Heat on stove over medium heat until the sugar dissolves and bubbles are starting to form around the edges. Whisk in the malted milk powder and cook until fully dissolved. Remove mixture from heat.
Whisk the egg yolks together in a large bowl. Pour in about half of the malted milk mixture in a steady stream, whisking constantly to prevent the egg yolks from cooking. Pour the egg mixture back into the saucepan and return to the stove. Cook for another 2 minutes, stirring constantly.
Remove saucepan from heat and add the gelatin. Stir until the gelatin is fully dissolved. Add in the chocolate and stir until fully melted and incorporated. Let mixture sit and cool to room temperature, about 1 hour.
Whip the cream to soft peaks. Fold gently into the chocolate mixture. The mixture may look very liquidy now but it will firm up as it cools and the gelatin sets.
When the mousse seems thick enough to spread, you can assemble the cakes. Place 8 cake rings on a baking sheet lined with parchment paper or a Silpat. Use a 2 1/2" round cookie cutter to cut out circles from the cake. You want to have 3 circles of cake for each cake ring. Place a circle of cake into the bottom of a cake ring. Spoon some mousse in. Top with another circle of cake, some more mousse, and the final circle of cake. If you have room you can spoon some mousse on top, but depending on how soft your mousse is it might make it trickier for the cake to hold its shape.
Chill cakes in the refrigerator overnight.
Unmold cakes shortly before serving them. Dust a little cocoa powder on top if desired.