Monday, November 12, 2007

My Best Chocolate Dessert

I realize I'm beginning to feel more confident in pâtisserie when I start changing recipes, or using building blocks to create a different result. My favorite dessert of the moment started with Pierre Hermé's Dôme de mousse au chocolat.

The dome freshly unmolded from its (Ikea) bowl, then covered in cocoa and decorated with sloppy chocolate ruffles and a chocolate cookie on top. All photos here were taken on the fly, no time for styling!

The dome has two layers of syrup-soaked chocolate cake layer nestled in a chocolate mousse (mousse sabayon, no gelatin) with caramelized nuts sprinkled in. I first made it exactly according to Hermé's recipe, in a dome form, though I didn't cover the cake with chocolate icing. I found a simple dusting of cocoa was sufficient.

Unfortunately I served the cake still semi-frozen, so the texture inside is not as airy as it should be. And in case you're wondering, I cut out the back of a cereal box to serve as a cardboard round underneath the cake. I'll be buying some prettier rounds next time I go to Mora!

This dome can make a spectacular presentation, especially if one has a little more time than I did to decorate it nicely. But the big slices weren't that pretty, the left-over partial dome looked sad in the fridge, and I felt it needed a different texture to complement the mousse and cake.

So I decided to form individual portions using dessert rings. I then replaced the bottom layer with dacquoise. So now we have, from the top down:
- Cocoa dusted on top, with something to decorate: a caramelized nut, a chocolate fan...
- Chocolate sabayon mousse
- Chopped caramelized almonds (should have been hazelnuts but I prefer almonds)
- Chocolate génoise-like layer moistened with cocoa-flavored syrup
- Chocolate sabayon mousse
- Caramelized nuts
- Almond dacquoise

This photo shows the different layers, though I prefer to hide them in the mousse

Yes, this dessert takes a long time to make. I make it over several days. The dacquoise keeps a long time, and I have circles of cake layer in my freezer as we speak, awaiting the next batch.

But what makes it all worthwhile is I can freeze the finished desserts, and defrost them over the course of a dinner. So when impromptu guests come by, I can whip out a stunning dessert in no time.

Well that's the theory. Unfortunately, my husband and I usually polish these off before anyone can suprise us with a visit.

Sprinkle the cocoa at the last minute, or it will start looking wet on the edges as in these photos. I tried to improvise some chocolate ruffles, and my hurry shows. But no matter how misshapen, these fans can always serve as a decoration.

A simple caramelized almond also serves as decoration. I'd also like to try the more elaborate caramelized hazelnuts shown here.

Recipe: Chocolate Mousse Cake with Caramelized Almonds
Source: Adapted from Pierre Hermé, Secrets Gourmands (Yikes, out of print? I bought it last summer, and for a fifth of the price listed here... It's a small hardcover book with gorgeous photos, but too many mistakes and typos. In any case, the following recipes can also be found in the Larousse du Chocolat).

For the syrup
This step is easy, so make it ahead to get it out of the way.
- 100ml water
- 50g sugar
- 15g unsweetened cocoa
Mix sugar and cocoa in a small pot. Add water, and bring to a boil while whisking. Leave to cool.

For the cake layer ("biscuit au cacao")
Can be made ahead. Store in the fridge tightly-wrapped for 2 or 3 days, or freeze.
- 100g egg yolks (5-6 egg yolks)
- 100g egg whites (3 egg whites)
- 20g flour
- 20g "fécule" (I used corn starch, but I think fécule is potato starch)
- 20g unsweetened cocoa
- 45g melted butter
- 100g sugar
Preheat oven to 230°C.
Sift flour, corn or potato starch, and cocoa. Whip egg whites with half the sugar. In another bowl, whisk egg yolks with the rest of the sugar till they become white and fluffy. Add 2 TB of this egg yolk mixture to the melted butter. Fold the whites into the yolks, then very delicately add the flour mixture, and finally the melted butter mixture.
Spread the batter evenly on a baking paper-lined cookie sheet, about 1 cm thick. Bake for 8 to 10 minutes. The cake should be barely cooked through. Let cool. Cut out circle shapes using a dessert ring as a cookie cutter. Store tightly covered. You can freeze them at this point.

For the dacquoise layer
Can be made several days ahead.
See this post for more details
- 135 g ground hazelnuts or almonds
- 150 g icing sugar
- 5 egg whites (save the yolks for the mousse, below)
- 50 g sugar
Preheat oven temperature to 170°C.
Sift together the ground nuts and icing sugar. If this is difficult to do, grind whatever doesn't make its way through the sieve. See post linked above for more details.
Whip the egg whites until firm, gradually add the regular sugar as you go. Using a flexible spatula, delicately incorporate the nut and icing sugar mixture.
On a cookie sheet that has been covered with parchment paper, spread the batter to about 1 cm thickness. Bake for 35 minutes.
Let cool, and cut out circle shapes using a dessert ring as a cookie cutter. Store tightly covered.
You can freeze them at this point as well, if possible in a rigid container to prevent breakage.

For the mousse ("mousse sabayon")
The mousse must be used as soon as it is made, so prepare it only when you are ready to assemble the cakes.
- 300g 70% dark chocolate (Hermé recommends Valrohna Guanaja)
- 1/2 liter of whipping cream
- 2 eggs
- 5 egg yolks
(so you need 7 eggs total, of which you do not use 5 egg whites.)
- 140g sugar
Melt the chocolate in small pieces in a water bath or in the microwave oven. Let it cool to 45°C. Put the sugar in a pot with 3 TB of water, let boil for more or less 3 minutes, or until the surface is covered in large bubbles (125°C)
[Astrid's note: I use a thermometer, and pull the syrup off the heat when it reaches 120°C, see below why].
Put the whole eggs and the yolks in a bowl and whip them while slowly drizzling on them the hot syrup.
[Note: this is where I've had problems in the past: the syrup sometimes hardened into a ball that almost prevented my hand-held mixer whisks from turning. I fished out the ball, threw it out and made some more syrup. My tips: make sure you don't pour the syrup on the whisks themselves, but rather in the egg directly, and perhaps undercook the syrup slightly.]
Place a large bowl in the freezer for 10-15 minutes. Use it to whip the cream. Add one quarter of the cream to the chocolate, then all the rest of the cream, and finally the egg-syrup mixture, folding gently with a whisk.
[Note: definitely use a whisk, not a spatula. I've had some problems with the chocolate hardening into little flakes on contact with the cream. Do make sure it is 45°C when you mix it with the cream. And anyway, if you eat the mousse with the caramelized nuts and the cake layers, you won't notice the chocolate flakes.]

For the caramelized almonds
These can be made several days in advance if you store them air-tight.
(I halved the recipe)
- 200g hazelnuts or almonds
- 125g sugar
- 35 ml water
- 1/4 vanilla pod (seeds scraped out)
Roast nuts in 170°C oven for 12-15 minutes
[Note: for the almonds I find this is too long, I roast mine about 7 minutes as they continue to roast in the hot caramel. Perhaps however for the hazelnuts you need 12 minutes to help get their skins off].
Boil sugar and water and vanilla pod and vanilla seeds in a large pot. When mixture is 118-120°C, throw in the warm nuts, remove pot from the heat and mix vigorously until sugar crystallizes around the nuts. Return the pan to heat and keep stirring until the sugar turns amber and there is almost no trace of crystallized sugar left on the nuts (I always have a little left, as I'm afraid of burning the caramel). Pour contents of pan on a silicone mat (or baking paper?) and gently separate nuts. Leave to cool and harden.

This is how I assemble my cakes, but there may be other methods. I usually build them upside down, then turn them over when I unmold them.
1. Prepare the rings
I use a small cookie sheet that fits into my freezer, and line it with baking paper. I place the rings on the sheet, and line each with special plastic called rhodoid or papier guitare, I forget which. Is it acetate in English? This makes unmolding easier, but is not required.
2. Fill the rings, assembly line-style
I spread a thin layer of mousse (using a pastry bag is helpful but not required). I sprinkle it with chopped caramelized nuts, then cover with a disk of chocolate cake brushed with syrup. More mousse, more nuts, and then finish with a disk of dacquoise.
3. Freeze for a few hours or overnight (or as long as you can resist the temptation...)
4. Unmold the cakes onto serving plates, turning them upside down so the dacquoise is on the bottom. Remove the rhodoid before the cake thaws; this will give you crisp edges. If you didn't use rhodoid, then warm the ring with a hairdryer and gently push on the dacquoise to extract the cake from the ring. Place in the refrigerator for a little while to thaw cake.
5. Decorate
Remove from fridge 15 minutes before serving to take off the chill, and at the last moment dust with unsweetened cocoa and decorate with chocolate ruffles or a caramelized nut.

Fewh! Hopefully you've made about 12 of these and have enough in the freezer to last you for another meal at least. Then I just might suprise you with an impromptu visit...

Variation: Making a dome
If you want to make the dome rather than the individual portions, use a bowl with a 20cm diameter. Cut out cake or dacquoise disks that are 14cm and 18cm in diameter. The smaller one goes in after you've filled the first half of the bowl with mousse, then comes more mousse, then the larger disk.
If your bowl size is different, then adjust the sizes of the disks, but you don't need to do a lot of math, you can eyeball the size of disks you need. If the disks are a little too small, they'll just be buried in the mousse.
To unmold, Hermé says to immerse the bowl for 10 seconds in lukewarm water. I used boiling water, and it took more than 10 seconds, but then the surface of the dome wasn't very smooth. Also my pretty Ikea bowl has no lip for my fingers to hold onto, which made it a little hard to handle.

And with the left-overs?
I never have enough rings, so I simply layer the mousse and cake into individual bowls, and serve directly in the bowl without unmolding. This informal presentation tastes just as good, and gives all the more reason to enjoy these "en famille"!