Friday, September 20, 2013

fudgy chocolate sheet cake

airplane cake

My son’s first birthday cake was a banana cake with fudge frosting and it was shaped like a monkey with a mini-monkey smash cake. Because he loved them so much, his second birthday cake had to involve graham crackers, but in my carried-away hands it turned into a s’more layer cake (in the book) with a milk chocolate filling and a marshmallow frosting that was toasted because really, how could I not? His third birthday cake was a celebration of fall and trains — apples, applesauce, pie spices and a subway map on top because he was then and still is subway-obsessed. And I had already started plotting his fourth birthday cake — something involving massive pillows brown sugar-broiled peaches and sour cream, with the faintest trace of nutmeg, all late summery and perfect — when I had the strangest idea, something that hadn’t once occurred to me before: I asked him what kind of cake he wanted, and do you know what he said?

“Tchocolate. Chocolate with chocolate.”

what you'll need
dark brown sugar + butter

My husband and I have this joke when he talks because he’s sometimes so frighteningly articulate* that it’s impossible to pretend that we can’t understand what he said, even if we’d prefer to (such as when he requests spaghetti for dinner again or only wants to go to the playground furthest from our apartment). So, we say, “gosh, Jacob. You really have to stop mumbling.” and then he said,

CHOCOLATE. BROWN TCHOCOLATE. NOT WHITE TCHOCOLATE.”**

chocolate sheet cake batter

And I’m such a terrible parent that I was kind of bummed because I thought the peach cake could have been kind of grand but now I was going to have to make a totally boring chocolate cake. Like anyone needs another chocolate cake recipe. I mean, sheesh, I have, what, seven in the archives alone?

very rich chocolate sheet cake

But when I got down to picking one, I ran into trouble. My first choice, the most decadent and tender one to date and it contained a full 1 1/2 cups of coffee, 3 cups if I doubled the recipe as I planned to make a sheet cake. I probably could have used decaf, but that still has trace amounts of caffeine and what kids like coffee flavored stuff? I probably could have used milk instead, but that’s a lot of flavor loss. I rejected the chocolate butter one that was my previous go-to for big events for being really sturdy and moist, but not decadent enough. I came back to, as I have no fewer than three previous times, sometimes as a loaf, sometimes as a disc, sometimes with buttermilk, sometimes with wine. Because it’s essentially a one-bowl cake. Because the crumb is downright fudgy. Because something magical and rich happens when you use dark brown sugar with cocoa powder. Because it’s insanely dark and decadent for something without a stitch of melted chocolate in it.

my freezer is just a mess

Wait, no melted chocolate? How can that be, you ask? The reason why this cake works not only well, but possibly better despite having only cocoa and no melted bar chocolate in it, harkens back to what I call The Alice Medrich Cocoa Theory, which she introduces along with her world-famous cocoa brownies. Basically, a bar chocolate contains cocoa solids, fat (cocoa butter) and sugar. To make cocoa powder work in recipes, you need to add additional fat and sugar. Medrich asks, why use cocoa butter if you could use real butter? I add to that, why use regular white sugar if you could use sticky, irresistable dark brown sugar? Essentially, good cocoa powder + butter + dark brown sugar potentially has way better flavor than melted baking chocolate. It just does. If you don’t believe me…

leveling a frozen cake layer

Well, fine then.

instant fudge buttercream

No cake for you.

instant fudge bloops

(More for us!)

so much fudge buttercream
a very tall chocolate/chocolate cake
crumb coat
pale blue sky
blue sky, red plane
airplane cake
airplane cake
a slice of sky

* Hm, do I sound like a humble-braggy parent? Okay, I’ll see you the “frighteningly articulate” and raise you the fact that he’s been scared to fly a kite because in one of his Curious George books, the kite takes George away. Hm, okay, that was just sweet… I’ll raise you the fact that he usually tries to eat yogurt with a fork, despite any evidence that this is a way to potentially succeed at eating yogurt.

** This, too, is my fault. When we’d go out for our nightly gelato in Rome, my son only wanted chocolate, and after the third night of scrubbing saturated chocolate messes out of his clothes, I decided to talk him into this “other, maybe better?” kind chocolate gelato called white chocolate. It worked for a day or so before he more or less called b.s. on it and started demanding “real” or “brown” chocolate. And really, who am I to argue? Dark chocolate is better. Signed, The Gelato Laundress.

cheese crackers + grahams + crispsairplane grahamslittle sandwiches from frescomama wants you to eat your veggies

And then there was a party: I mean, of course. Four is major! After a panic on Friday learning that our chosen/paid-for destination would have to close for the weekend, we decided to use the space anyway and bring in a face-painter, balloon guy and guitar player that all the mamas swooned over. I mostly reined in my obsessive homemade tendencies, only making some airplane-shaped goldfish crackers and grahams this year; we ordered sandwiches, my mother made iced sun tea and lemonade, my in-laws brought watermelon and balloons (though, one bundle had other priorities). Let’s see… oh, I found these amazing printables online that made me look like a far more coordinated and doting party-planner than I am; I’m not sure that’s actually a lofty goal but those jars sure looked pretty! And you can’t have an airplane party without having airplane favors; we picked up one of these a Cracker Barrel on our way to Maine last month and we played with it for an hour a day until it broke and still considered it the best $4 ever spent on a toy. Now we have a case!

UK Book Tour: I’m in London! I’m in London! Well, for a few hours and then I’m en route to the Abergavenny Food Festival (you should have heard how politely the cab driver laughed when I pronounced Abergavenny the way I thought it might sound last night!) tomorrow and then back in London and Bath and Cambridge. The full schedule is here. I hope we’ll get to meet. I will try not to gush too awkwardly over your delicious accent.

One year ago: Fig, Olive Oil and Sea Salt Challah and Roasted Apple Spice Sheet Cake (last year’s birthday cake)
Two years ago: Roasted Tomato Soup with Broiled Cheddar
Three years ago: Linguine with Tomato-Almond Pesto
Four years ago: Corn Bread Salad and Chocolate Pudding Pie
Five years ago: Sour Cherry Compote and Cold-Brewed Iced Coffee
Six years ago: Lemon Layer Cake
[New!] Seven years ago:
Chocolate Caramel Cheesecake and Moules a la Mariniere

Fudgy Chocolate Sheet Cake

This is the sheet cake you make for someone you love very much, someone worth splurging on Dutch-process cocoa for (I won’t lie, this is my favorite, and I save it for my favorite people), and then using a lot of it. It’s fudgy and moist and deep dark brown, and the crumbs are so loosely tethered to each other that it would truly benefit from another egg (there will be crumbs when you cut it) but I refuse because I don’t want the additional sturdiness that another egg would impart.

I got a little carried away and made this cake monstrously huge (6 inches tall!) — 3 layers of chocolate cake + 2 layers of fudge buttercream filling + vanilla buttercream (tinted blue and other colors) for the outside. This cake was 6-inches tall and fed a huge crowd. However, the recipe below is for the more manageable size I’d intended — 2 layers of cake (each is an inch tall) + 1 layer of fudge buttercream filling + vanilla buttercream for the outside. To make it the way I photographed it, increase the chocolate cake by 150% and bake it in three layers and double the fudge buttercream filling so that it will fill two layers. I’d estimate the servings for the triple-layer version as 52 (cut 4×13). For the double-layer version below, I’d estimate the servings as the same (for slices that will feel smaller with less height), 36 (cut 3×13) or 40 (cut 4×10).

The cake design was inspired by this one and this other one that I found through a Google image search.

Substitutions: Don’t have buttermilk? You can make an approximation of your own. Same with brown sugar. Even baking powder, but let’s not get too crazy.

New to layer cakes? These are my favorite tips.

Note: The volume of batter below (for a 2-layer sheet cake) could be used to make a tall 3-layer 9-inch cake. [If you have The Smitten Kitchen Cookbook, you'll see this there, with the buttermilk replaced with red wine, as the Red Wine Velvet Cake with Whipped Mascarpone.] You could also use the batter to make 32 cupcakes, as I did on Tuesday for my son’s preschool class. A 1-cup (8-ounce) butter level of vanilla buttercream (half with 2 ounces melted and cooled unsweetened chocolate beaten in) yielded way more frosting than needed for a normal, not towering, level of frosting on each; I might recommend scaling the recipe to 3/4-cup (6-ounce) instead.

Cake layers
1 cup (2 sticks, 8 ounces or 230 grams) unsalted butter, at room temperature
2 cups (380 grams) firmly packed dark brown sugar
2/3 cup (135 grams) granulated sugar
4 large eggs
2 cups (475 ml) buttermilk
2 teaspoons vanilla extract
2 3/4 cups (345 grams) all-purpose flour
1 1/3 cups (115 grams, approximately) Dutch-process cocoa
1/2 teaspoon baking soda
1 teaspoon baking powder
3/4 teaspoon table salt

Fudge buttercream filling
2 ounces unsweetened chocolate, melted and cooled
1 1/2 cups confectioners’ sugar (no need to sift)
1/2 cup (1 stick, 4 ounces or 115 grams) unsalted butter, at room temperature
2 tablespoons half-and-half or whole milk
1 teaspoon vanilla extract

Vanilla buttercream frosting
1 cup (2 sticks or 230 grams) unsalted butter, at room temperature
3 3/4 cups (1 1-pound box) powdered sugar, sifted
4 tablespoons half-and-half or whole milk
2 teaspoons vanilla (use less if you want a whiter frosting)

Make cake layers: Heat oven to 325°F. Line the bottom of two 9×13 rectangular (i.e. quarter-sheet) cake pans with parchment paper. Grease parchment and sides of pan. Using an electric mixer, beat butter with sugar in a large bowl until light and fluffy. Add eggs, one at time, beating each in until just incorporated and scraping down sides of bowl. Add vanilla, then buttermilk. (Don’t worry if the batter looks a uneven and grainy; it will all be fine in a minute.)

Place flour, cocoa powder, baking soda, baking powder and salt in a sifter over the mixing bowl and sift ingredients in. Beat or stir dry ingredients into batter until just combined; scrape down bowl again. Divide batter between two pans. Bake each layer for 30 to 40 minutes, rotating them once top-to-bottom and back-to-front halfway through. Cakes are ready when a toothpick inserted into the center of each layer comes out batter-free. Cool in the pan 10 minutes, then remove cakes from pans and let cool completely on racks. I often put those racks right into the freezer, to firm up this very soft and tender cake before leveling and frosting it; it makes the process much easier.

Make fudge buttercream filling: Place all of the ingredients in a food processor and pulse to incorporate, then process until the frosting is smooth. If you don’t have a food processor, you can beat the butter until light and fluffy with an electric mixture, then add the sugar and melted chocolate, followed by the milk or cream and vanilla. With an electric mixer, it helps to sift the powdered sugar first.

Fill cake: Remove first cooled cake layer from freezer. Place on cake board or serving tray. Arrange small scraps of waxed or parchment paper underneath edges, to protect the cake plate from frosting as you decorate. Level the top of the cake if it has domed by shaving off the dome with a horizontal serrated knife. Put the cake scraps in the garbage and cover them with dish soap; nothing good will come of it otherwise. Spread fudge buttercream filling evenly over first cake layer. Place second layer on top of filling; you can level this too slightly if it it has dome, but it’s less essential to the stacking of the cake if it’s the top layer. Return the cake to the freezer, while you make the frosting. Having it very cold will make it easier to cover the chocolate crumbs with your light-colored frosting in a few minutes.

Make vanilla buttercream: You can make this either in the food processor (using the same method as the fudge buttercream, above) or with an electric beater, however, I find that I can get this frosting fluffier by hand with the latter, via electric beaters or a stand mixer. Beat the butter until light and fluffy in a large bowl. Add sugar 1/2 cup at a time (trust me on this, it allows us to get away with less sugar than the standard recipe) until fully incorporated. Beat in half-and-half then vanilla.

Frost and finish cake: From here, you method will vary depending on your intended decorations. I put 1 cup frosting in a separate bowl for the piped decorations (clouds, planes and writing) and tinted the rest with just one drop of a concentrated blue color. (I love this stuff.) Thinly coat entire cake with frosting (this is a “crumb” coat, to mask the chocolate crumbs better), then return the cake to the freezer for 10 minutes, to set the first layer of frosting, then finish frosting the cake with the remaining frosting. Tint and pipe any decorations needed with remaining buttercream.

To serve: If making this the day before the party (recommended!), keep it in the fridge overnight. If you want it fully defrosted for a party that day, an hour or so at room temperature should be sufficient. It doesn’t hold the cold in very long.


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