Friday 8 August 2014

Chocolate Cherry Chestnut Torte

Every year, as Jon's birthday approaches, I ask what kind of cake he would like. Invariably, the response has been the same: "something chocolate." This leaves things very much open to interpretation. As you may have noticed, there are a lot of very different things that can be considered chocolate cake. So, as usual, I found myself looking through lots of recipes for ideas and some points of reference - after all, cakes aren't something I make very often, so it's the least I can do to make sure his birthday cake actually tastes like...well, a birthday cake. But did I mention that there are a lot of kinds of chocolate cake? Fluffy and light, rich and fudgy, dense and flourless, elegantly simple, extravagantly layered...there is no basic formula, because there are so many different approaches. All are delicious, but in such different ways. How to even begin to choose?

It would be an exaggeration to say I completely scrapped all those recipes I was comparing and just improvised, but it's actually not such a huge overstatement. The recipe I ended up with doesn't quite fit any standard ratio I've previously followed, and it probably breaks some rules here and there as far as what "should" go in a cake, or the order in which things are usually done. Yet the results speak for themselves. Despite any rules I may have broken, the cake is light-textured, tender, moist, and rich, and pairs wonderfully with the equally delightful fluffy frosting. I'm really pleased with how it turned out - and I think if you try it, you will be too.

First, the flavor: The cake has some cherry juice in it, which complements the cherry filling and really brings out the fruitiness of the chocolate. I had some homemade almond milk on hand from another project, so I used it in the cake in addition to almond meal, to further emphasize the cherry-almond combination (cherries and almonds, after all, are related, and there is some overlap in the chemistry of the flavors we associate with them). Even if you usually use regular milk, I highly recommend almond milk in this recipe for the depth of flavor it contributes.

The cake itself is similar to a genoise, containing a significant proportion of nut meal and getting its light structure from a well-developed egg network rather than any added binders. Unlike most other sponge-type cakes, though, it also features two other distinctive flours, which also happen to be two of my favorites: chestnut (as you can tell from the title), and buckwheat. If you associate buckwheat with a "harsh" or intrusive flavor, as I often see recipes describing it, you might be surprised to see it in such a delicate cake. Let me tell you something: buckwheat should not be harsh. From what I understand, that flavor - as well as the dark, gritty appearance often associated with it - comes from small fragments of the bitter black hull remaining mixed in with the grain. I grind my own buckwheat flour, and the difference is striking. I'm not using any special variety of buckwheat, it's just that buckwheat packaged as whole grains will usually have any trace of hull removed. Its flavor, while still distinctive, is mild and pleasantly nutty. As you can see, the color is also much more appealing - almost creamy. I highly recommend giving it a try. If you don't have a high-powered blender or food processor, try grinding small amounts in a clean coffee grinder.

Front: fresh-ground buckwheat;
Back: store-bought buckwheat flour.
Difference: huge!
As for the chestnut flour, I'm lucky to have a good local source; if it's not available where you are, try substituting coconut flour - it will definitely change the overall flavor composition, but I'm sure it will be equally delicious.

I'd planned to complement this cake with a meringue buttercream, both because it's a special occasion and because a sponge-type cake like this is best with something less overwhelmingly sweet than standard powdered-sugar frosting. Just a couple of days ago, though, my kitchen thermometer spontaneously broke! (It's stood up to the high temps of deep-frying and candy-making, but apparently measuring the temperature of a warm water bath was just too much for the glass to handle...) Yes, I know, a lot of people make meringue icings without needing a thermometer and everything turns out fine, but since I've only made them on a couple of occasions, I didn't want to risk it. I was very much not in the mood for last-minute thermometer-hunting, so I decided to go hunting for a different frosting recipe instead.

Well, I never thought I'd say this...but I'm kind of glad my thermometer broke. If it hadn't, I might never have discovered this frosting! It's creamy and rich-tasting, yet it is not too sweet, and it is very light, not at all oily or heavy the way some buttercreams can be. It's still a cooked frosting, but it's pretty unusual as far as those things go - rather than egg white, the thickening comes from making a sort of pudding with starch and milk, and it uses regular granulated sugar instead of powdered sugar...but the sugar is creamed right into the butter! The trick is letting the mixer run a long time - eventually the sugar will be fully incorporated, not grainy, and the thick starch pudding will be transformed into velvety, buttery fluff.

Chocolate Cherry Torte

Makes a 2-layer, 8" round cake, with frosting and cherry filling.

Because the richness in the cake comes from the chocolate, egg yolks, and almonds rather than butter or milk, the cake itself happens to be dairy-free. The frosting and filling, on the other hand, are very much dairy-full; however, I've included a note at the bottom with some suggestions if you cannot tolerate dairy.

For the cake:

80 g almond meal
60 g chestnut flour
60 g buckwheat flour (see above)
25 g arrowroot starch
2 tsp aluminum-free baking powder (I used Rumford)
1/2 tsp sea salt

170 g sugar
3 eggs, room temperature (mine weighed 155 g total)

240 g unsweetened almond milk
120 g cherry juice, very hot

60 g semisweet chocolate chips
50 g high-quality cocoa powder (look for one with relatively high cocoa butter content)
1/2 tsp almond extract
1/2 tsp vanilla extract

Preheat oven to 375ºF/190ºC. Prepare two 8" round pans, lining bottom with parchment and buttering lightly.
Pour hot cherry juice over chocolate and cocoa in a small bowl, stir to combine, and set aside (stir occasionally to make sure mixture is completely smooth). In the bowl of a mixer, combine eggs and sugar. Beat on medium-high for a few minutes, until foamy and glossy. This network is what will bind the batter, as well as trap air to provide leavening, so don't rush this step!
Add flour mix (including salt and baking powder) to the egg foam approximately 1/3 at a time, alternating with almond milk 1/2 at a time, stirring slowly after each addition and taking care not to deflate egg mixture. Stir vanilla and almond extract into cooled chocolate/juice mixture, then very carefully fold mixture into batter by hand, until just combined. Gently pour batter into pans, place both pans on insulated baking sheet, and bake 45-50 minutes, until cooked through to center.
Cool 15 minutes in pans, then turn out onto cooling rack. Make sure cakes are completely cooled before proceeding.

For the frosting:

The recipe I adapted this from calls it a custard frosting - despite the fact that it contains no eggs, this is a pretty accurate description of its flavor and texture. My special twist is using goat cheese in place of half of the butter, which gives the mixture a cheesecake-like flavor. This does admittedly make a softer, even lighter-textured frosting - if you want to be able to pipe it decoratively like shown in the link, it's probably best to stick with all butter. I just really love the subtle tartness the goat cheese contributes. (I think cream cheese would probably work too, though I haven't tried it.)

240 g whole milk
200 g granulated sugar
32 g starch (cornstarch recommended; see note below)
112 g unsalted butter, room temperature
112 g plain goat cheese
pinch salt
1/2 tsp almond extract

Combine milk and starch in saucepan and heat gently, with stirring, until thickened. Remove from heat and set aside to cool, stirring several times as it cools. Meanwhile, put sugar, butter, goat cheese, and almond extract in the bowl of a mixer and beat on medium-high for 4-5 minutes, until light and well-combined. It may seem more intuitive to add the sugar to the liquid, to dissolve it that way. Don't do that! The sugar would tie up too much of the liquid, leaving not enough free liquid for the starch to fully expand - meaning it won't thicken as well as it should, and will still have a raw starch aftertaste. (Trust me, I tried it.) When pudding mixture has cooled to room temperature, add it to the mixer bowl and beat a few more minutes, until fluffy and smooth.

For the filling:
120 g frosting, above
60 g additional goat cheese
50 g chocolate, chopped into small pieces
100 g high-quality jarred cherries, well-drained and roughly chopped (look for tart cherries with no added colors, in juice or sugar or in brandy/liqueur; not pie filling)

Combine frosting and cheese. Gently fold in chocolate and cherry pieces until just combined.

To assemble the cake: Spread filling mixture thickly between cake layers. Chill briefly before proceeding with frosting the rest of the cake, to ensure the filling does not get squished out the sides.
Frost sides and top of filled cake. If desired, decorate the top of the cake with cherries, finely grated chocolate, and/or almond pieces.
Keep decorated cake refrigerated.

Note about starch: The frosting pictured was made with arrowroot starch, which - as I would quickly discover, much to my dismay - apparently does not mix very well with dairy, becoming stringy and gloppy when they are combined over heat. While I was eventually able to force it to cooperate through extensive mixing (and a couple of spoonfuls of powdered sugar), I advise against using arrowroot in the frosting. I'm recommending cornstarch as per the original recipe linked above, but I confess I have not tested my full recipe as written with cornstarch, nor have I tested other starches such as tapioca.

Note about dairy substitutions: I honestly don't know yet whether this frosting would work with non-dairy milks - I'm not sure whether or not the milk is essential to the pudding thickening properly. If you want to be sure the frosting will turn out right, it might be better to use a recipe that does not call for dairy. If you do wish to experiment with this recipe, though, I would suggest possibly altering the procedure slightly depending on your ingredients. Since many ingredients used in baking as natural alternatives to butter (coconut oil, palm shortening, etc) are entirely fat, whereas butter contains some water, I think there's a chance the sugar may not be able to dissolve as completely. If you want to experiment with one of these fats, you might try reserving a small proportion of your chosen milk substitute and stirring that into the sugar before adding it to the creamed fat, then proceeding using the rest of the liquid for the pudding base as written. Blended butter substitutes (spreads, etc.) will contain some water, so while I haven't tested it to be sure, I would guess those would probably work with the regular method.
If you try making this frosting with non-dairy ingredients, please let me know how it turns out!

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