Recipe: Posie Brien's Forever Go-To Chocolate Sheet Cake

I plan to celebrate the completion of the Breaducation manuscript later this year with a “no-bread party,” a feast at which there will be zero bread products of any kind served.

One of the items I definitely plan to include is my pal Brien’s chocolate sheet cake, a recipe that has become my go-to cake for many occasions, and the only chocolate cake I reach for anymore, because it is dead easy to make—it’s a no-mixer, dump-and-stir recipe using mostly pantry ingredients—and 100% perfect: rich, moist, and deeply chocolatey, despite containing little more than a scoop of cocoa powder.

And I’m not the only one who has come to love this recipe as much as I: After a friend tried it, she volunteered to make dozens of them for not one but two weddings, and it was a big hit at both. And it’s sure to be a big hit for Valentine’s Day this year, should you have someone special to bake for (even yourself).

The version here is my adaptation of Posie’s, though the differences are minor. First, I scaled it up by 1/3, so it makes a slightly taller cake. And secondly, I added notes about substituting yogurt for the buttermilk and even the sour cream, something I do all the time without negative consequences. (I don’t keep sour cream or buttermilk on hand, but I always have homemade whole-milk Greek yogurt, so I can make this cake without a trip to the supermarket, in an emergency.) You can find Posie’s original version here, should you want to make that one instead.

One last thing: I have successfully made and frozen this cake, and I think the texture— perfect to begin with—is actually made more perfect after freezing and thawing it, something I believe is true for many cakes; it seems to deepen the fudgy, pudding-like quality it already has. Be sure to wrap it very tightly, and don’t leave it in the freezer for more than a week or two. To thaw it, let it sit at room temperature, still wrapped, for at least 12 hours.

I asked Posie to write a little something about her own feelings on this cake, which are similar to mine.

—Andrew

Posie Brien: As an eater, a very good chocolate cake is not hard to find. But as a baker, I’ve found the challenge to be incredibly daunting. Most of the recipes recommended to me—by friends or fellow bakers or cookbooks I trust—yield a batter so thin and liquidy it sloshes around the bowl. Those recipes result in cakes that are fine. Serviceable. The crumb is moist and the cake itself tender, but the chocolate flavor always seems muted: a shadow of what I expect from a truly excellent chocolate cake. 

Disheartened, I turned to other templates. I made chocolate butter cakes. Flourless chocolate cakes. Chocolate cake with hot coffee and chocolate cake without it. Malted chocolate cake. 

To spare you from the trials, I’ll present you with my forever go-to chocolate cake. It’s not an intense, rich, need-to-sit-down-after-one-bite affair but nor is it tepidly chocolate in flavor. The crumb is dreamy: the sort of tender and dare I say damp interior I dream of in a sheet cake. Picture this if you will: You finish your slice, and a few scattered crumbs remain. You press the tines of your fork into them and they all smoosh together into a chocolate-y mass. That is what we’re after. Nothing dry, but also not so damp that the cake lacks structure. 

This is a cake you can spin into endless variations. I love it with a pillowy whipped chocolate frosting, but take it any direction: malted frosting, thick chocolate ganache, ermine frosting, vanilla buttercream topped with sprinkles, swoops of Swiss meringue frosting flavored with raspberry or caramel or rum! 

I bake it as a sheet cake because it’s simple and fast, but the sour cream gives it enough structure that you can easily bake it as a layer cake. Or leave it unadorned with a dusting of confectioners’ sugar or a dollop of whipped cream and call it breakfast.

Posie Brien's Forever Go-to Chocolate Sheet Cake

Makes one 9” x 13” cake

• There should be enough frosting here to cover the entire cake modestly, or the top very generously.
• Andrew makes this with whole-milk Greek yogurt in place of the sour cream (along with Greek yogurt and water for the buttermilk), and he thinks it comes out great that way.
• You can also use this to make two 9” round cakes
  
  

CAKE

2/3 cup (152g) sour cream (or Greek yogurt)

1-1/3 cups (320g) buttermilk (or 127g Greek yogurt and 194g water)

4 large eggs, at room temperature

2/3 cup (158g) very strong brewed coffee

2/3 cup (150g) vegetable oil

2-1/2 teaspoons vanilla extract

4 cups (560g) all-purpose flour

3-1/2 cups (700g) granulated sugar

2/3 cup (60g) cocoa powder, preferably Dutch processed

2/3 teaspoon baking powder

2 teaspoons baking soda

1/2 plus 1/4 teaspoon kosher salt

FROSTING

1 cup (170g) semi-sweet chocolate chips

1 cup (2 sticks) unsalted butter, at room temperature

2 cups (230g) confectioners’ sugar

2 teaspoons vanilla extract

pinch of salt

1. CAKE: Preheat the oven to 350˚F (175˚C). Grease (or line with parchment) a 9” x 13” pan.
2. Whisk together the sour cream, buttermilk (or yogurt and water), eggs, coffee, vegetable oil, and vanilla. Set aside.
3. In a large bowl, whisk together the flour, sugar, cocoa powder, baking powder, baking soda, and salt.
4. Add the wet ingredients to the dry ingredients and mix until just combined.
5. Pour the batter into the prepared pan and bake for about 45-55 minutes, or until the cake springs back lightly when you press the surface. Remove from the oven and let cool while you make the frosting.
6. FROSTING: Melt the chocolate chips (in the microwave or over a double boiler), then set aside to cool slightly.
7. In the bowl of a stand mixer, beat the butter with the confectioners’ sugar, vanilla, and salt until fluffy. Add the melted chocolate and beat until well-combined and fluffy.
8. Frost the top of the cake and add lots of sprinkles, if you’re into that. Or not. It’s your cake; do your thing.