This was on an episode of America’s Test Kitchen a while ago and it looked so good I thought I would try it. It’s actually quite easy to make, but be prepared to make it over the course of a day because the layers take some time to firm up. Your patience will be very well rewarded.
I will not repeat the recipe here because it can be found at the America’s Test Kitchen website. You may have to login to their site, but it’s a simple registration that doesn’t cost anything.
First thing you will need is a good spring form pan. This is a pan where the sides of the pan separate from the bottom and there is a little latch (spring) that will snug the sides onto a dado in the bottom disk. This recipe is built for a 9.5″ diameter by 3″ deep pan. I got my pan at Crate & Barrel and it measured 9″ x 3″ and worked well.
Next, butter the pan on the bottom and sides. Only one layer of this cake is actually cooked and that is the bottom layer. But you also want the spring form to release from the sides of the other two layers too. So butter the whole thing.
ATK (America’s Test Kitchen) has done a lot of study on the best types of chocolate. No doubt what they selected is going to taste the best. If you’re like me you can’t always get the exact brand of ingredient that they suggest. For instance they said that Guittard white Choc-Au-Lait white chips worked the best. Well, of course I couldn’t find any of those at my Whole Foods or Safeway. I’m using Ghiradelli white chocolate baking bar instead. They also suggested Ghiradelli bittersweet chocolate chips. Naturally I could only find semisweet. But that’s okay. Many times it’s difficult to tell the difference between bittersweet and semisweet.
The first layer of the cake has to be the firmest and sturdiest. Start by setting up a double boiler (a pyrex/heat resistant bowl that will sit just inside a pot on your cooktop). Put about an inch of water in the bottom of the pan (not the pyrex) and bring it up to a simmer with the bowl nestled on the rim of the pot.
Use 3/4 of stick of butter cut into about 6 pieces or about 6 tbsp. Measure out 6 oz of your brown chocolate of choice. In baking you can never go wrong by measuring things by weight and then it’s repeatable most times. I use a little Oxo scale.
The steam from the simmering water underneath the bowl is what is going to heat up the bowl and keep it at a perfect temperature to melt the chocolate. Don’t be tempted to just put it in a pot on the stove. You’ll be sorry.
If you just let it sit there it might not look like it’s doing anything, but it is gathering heat. Use a plastic spatula to begin stirring the mixture after a few minutes. Continue to stir every minute or so until it is all incorporated.
Once that is melted and all together, shut off the heat and use mits to lift the bowl out and set it aside to cool for a few minutes.
Meantime, with an electric mixer with a whisk attachment begin to whip the whites of four eggs together with a pinch of salt for about 30 seconds. Add half of a 1/3 cup of light brown sugar and mix until it is incorported. Then add the remaining half of the brown sugar and whip on high speed until the mixture can hold a soft peak. Because this cake is pretty delicate I make sure it can really hold the soft peak:
Now the fun begins. With your chocolate mixture now cooling down, whisk in four egg yolks and 1 1/2 tsp of vanilla extract into the chocolate. ATK calls for a bit of espresso powder too. I didn’t have any and it still turned out really well. But if you can take the caffeine and would like a more mocha flavor I would certainly suggest putting it in.
With your whisk pull out about 1/3 of the whipped egg whites and gently fold it into the bowl with the chocolate. The mixture will be streaky and then lighten up as it’s mixed in. After it’s gently folded in add the rest of the egg whites and fold that in with a plastic spatula. Using the spatula instead of the whisk will help to avoid getting any big air bubbles into the batter.
You’re now ready to build the first layer. Carefully pour and scrape the bowl into the bottom of your spring form pan. The batter will be pretty loose and should flow easily into the pan. You may start to see some air bubbles rise through the batter. This is good. In fact you can encourage it a little bit by gently lifting the pan about a finger width off the counter top and dropping it. Or gently tap on the sides to release some of the air bubbles.
Place this in a 325 degree oven and let it bake for about 15 minutes. Check it occasionally after it goes past 13 minutes. If you smell a lot of chocolate in the air that is not a good thing. Much of chocolate’s flavors are volatile and can disappear with too much heat or over cooking.
When the cake has a nice little skin all over the top and is just a little jiggly in the middle you are there. Take it out of the oven and place it on a cooling rack to cool. The cake will have expanded to fill much of the pan. That’s perfect and it will deflate as it cools to make room for the next layers. This bottom layer then needs to go into the refrigerator for at least 2.5 hrs.
The Middle Layer
Make sure that the first layer of the cake has had time to cool in the refrigerator for at least 2.5 hrs. You don’t want any warmth from the cake to mix into the cooler layers that are about to go on top.
The middle layer of this cake is all mousse….chocolates and whipped cream. You start by dissolving two tbsp of cocoa powder into 5 tbsp of hot water. ATK recommends, and I agree, that you use a Dutch processed cocoa powder. It isn’t as bitter as a standard cocoa powder and I think provides a smoother taste. I had some Nestle’s Dutch processed cocoa powder on hand and there were no complaints about taste from any of my guests. This mixture will be the consistency of a slurry of chocolate and it pours easily, but it’s not real watery.
The next step is to measure out 7 oz of bitter sweet chips and begin to melt those in the double boiler setup similar to the first layer.
Meantime, in your mixer with the whisk attachment, whip 1 1/2 cups of whipping cream with 1 tbsp of granulated sugar and just a pinch of salt (1/8 tsp). Bring it at least soft peak consistency.
With the chips melted, take the bowl off the boiler and whisk in the cocoa powder slurry with the chocolate.
The color will turn very deep brown as you can see below. Add a few dollops of the whipped cream mixure (about 1/3 of the mixing bowl) to the chocolate mixture. Use a whisk to fold it in to lighten the mixture.
Add the rest of the whipped cream folding it in gently with a rubber spatula until the mixture is a uniform color and consistency. Be careful not to mix air in that will turn into large air bubbles that could cause gaps in your batter later.
When you’re done the mixture will have lightened in color and texture considerably.
Pull the first layer that is still in the spring form pan from the refrigerator and carefully pour the new mousse mixture on top. You shouldn’t need to spread this around with a knife. It should settle pretty easily by itself and with a little bit of jiggling of the pan. As with the first layer I lift the pan about a finger width above the counter top and drop it a few times to jiggle any remaining air bubbles up through the mixture.
Set the pan back in the refrigerator. As it cools it will begin to firm up some more. You can proceed to the next step, but be sure to let it chill for at least 15 minutes. For me I was busy cleaning up the bowls from the previous layer and by the time I got everything together the second layer had been in the refrigerator for at least 1/2 hour. You can even come back to this much later to finish the third layer.
The Top Layer
Begin by sprinkling 3/4 tsp of gelatin powder like Knox Gelatine into 1 tbsp of cool water. Let that sit and as a few minutes go by the mixture will be sort of a granular gelatin.
Next, break off 6 oz of white chocolate and begin to melt it in the double boiler. I used the Ghiradelli white chocolate baking bar. This bar is already portioned into 1/2 oz squares. So I just broke off enough to make six oz rather than weighing it…thanks Ghiradelli.
While the chocolate is melting bring 1/2 cup of whipping cream to a soft simmer in a small pot on your cooktop. Once it has come up to a simmer, remove it from your cooktop and whisk in the gelatin. The gelatin will dissolve rapidly and you’ll never really see it again except that it will give the top layer a little body. White chocolate itself has no cocoa solids in it. It’s basically mostly cocoa butter which by itself doesn’t give a lot of body. The gelatin provides the body and still gives a very silky texture for the top layer.
Once the white chocolate has melted, remove it from the double boiler and whisk in the cream and gelatin mixture.
In your mixture, whip the remaining 1 cup of heavy whipping cream. There is no salt or sugar added to this whipping cream as the white chocolate provides enough sweetness by itself. As before, start by folding in 1/3 of the whipped cream with a whisk into the white chocolate. When that has been incorporated then add the rest of the whipping cream and gently fold that together with a rubber spatula.
You can now retrieve your first two layers from the refrigerator and pour the white mousse mixture on top. This mixture will be a little stiff and since it’s the top most layer it will require a little smoothing with the help of an offset spatula or other smooth blade. In my 9″ x 3″ pan this rose right to the very top. In the 9.5″ pan they recommend you will be below the rim which is where the offset spatula can come in handy to smooth the top.
Put this back into the refrigerator and let it sit for at least another 2.5 hours. If you’re like me it’s just much better to make it the day before you really want it. The cake will have ample time to set up and you won’t be tempted to pull it out before it’s time.
To be honest I don’t know if I’ve done anything wrong with the bottom layer. It was a little concave which I think occurred as it settled after bringing it from the oven. I can’t remember if the good folks at ATK were showing something similar or not. But I can tell you it did not affect the taste at all and everyone remarked at how professional it looked. Perhaps one of our readers here can confirm or deny an issue.
One gadget that I did not have in my kitchen was a piano wire cake slicer. After having done this cake once before and just slicing it with a regular knife I can say it can make quite a mess. So I was determined to have a more professional cut the next time. Don’t expect to find one of these at Crate and Barrel or Williams Sonoma. But it’s well worth the hunt by either going to a restaurant supply store or ordering online like I did. Of course as soon as I finally found it and ordered it I lost the URL. Managed to find it again. It’s about half way down this page and is called a “HandledCheese Wire.” http://www.fantes.com/cheese.html These things are cheap, but worth their weight in gold if you want a professional slice through a very soft cake. You’ll spend more to have it shipped than the $2.98 that it cost.
The final step before slicing is to dress it up on top. You can either sprinkle a little cocoa powder on top or do some chocolate shaving. I had a little milk chocolate bar handy. All you need to do is to use a vegetable peeler and rake it over the bar chocolate and you’ll get some nice shavings. Generously sprinkle these over the top and you’ll have a nice professional looking finish.
Well, there you have it. I’ll get better at the photography, but I can assure you if you do this recipe that anyone with a taste for chocolate will think they died and went to heaven.
What did I learn?
- Have a great spring form pan.
- Add to your kitchen gadgets with the handled cheese wire.
- Despite my unending respect for the work at America’s Test Kitchen it is possible to have astounding taste without using every ingredient they used. So don’t be hard on yourself. Improvise as you need to.
- This is much easier to do than it looks or sounds. It just takes some time so you need to plan ahead.
Things I want to try next time
- I want to try pulled the wire slicer horizontally under the cake to see if it helps to loosen the bottom of the cake from the bottom of the spring form pan with the hopes that lifting a slice out is easier.
- I wasn’t watching close enough, but I never did see ATK pull this cake from the bottom of the spring form. Yet you see cakes like this sitting in a gourmet bakery display case. Anyone know how to get a cake like this off the bottom of the spring form without destroying it? I thought about making a disk of parchment paper and then somehow sliding it onto a cardboard cake round. Not sure how easy it would be to pull a slice out that way without getting some paper too. Give me your comments if you’re familiar with how or if this is done.