Buttermilk Chocolate Chip Cake with Espresso-chocolate Frosting

So, this was my 33rd birthday cake.

I know. It kinda makes me want to turn 33 forever, right?

As we hosted a thank-you dinner party for some neighbors and friends on my actual birthday, my mama decided that I should have my very own birthday cake a week later (but really, now that I have a baby of my own, I know the real truth: birthdays are for mamas. Mamas are born the same moment their babies are, and will forever remember the entire day, or many, many hours that it took to get that little person–now a 33 year old woman who’s got a baby of her own– into the world. Celebrating a birthday is as special to the birthday girl or boy, if not more special, to her or his mama. At least that’s how my wonderful, selfless, perfect mama is.) This is my mama.Also, she’s an INCREDIBLE french bread baker, and artist, and the most precise person I know, but cake baking and cake-decorating isn’t so much her thing. She’s also still recovering from chemo, and surgery, and radiation several months ago, but she STILL made me this incredible chocolatey layer cake in the style of Momofuko milk bar (and based on her chocolate chip-passionfruit cake.) I don’t deserve my mama, y’all. If you want to show someone the love you have for them, and if food is your love language, then this cake is one sure-fire way to do it.

But about the cake…

Here’s the baking gear you need:

a quarter-sheet pan (so, 9’x13″)
a 6-inch cake ring OR what I used.. a 6 inch aluminum can (of baked beans, drained and super washed)
acetate sheets (but then, sicne we couldn’t get that in my tiny town, we used a laminated placemat, cut & taped to fit the can)
a freestanding blender
parchment paper
hours and hours of time

For the Buttermilk Cake (makes 1 quarter sheet cake):

1/2 cup (1 stick) unsalted butter, at room temperature
1 1/4 cups granulated sugar
1/4 light brown sugar, tightly packed
3 eggs
1/2 cup buttermilk
1/2 cup canola oil
1 tablespoon vanilla extract
1 1/2 cups cake flour
1 teaspoon baking powder
1 teaspoon kosher salt
3/4 cup mini chocolate chips

For the crumbs (2 1/2 cups)

1/2 cup granulated sugar
2/3 cup cocoa powder
1 teaspoon kosher salt
6 tablespoons unsalted butter, melted

1/2 cup (1 stick) unsalted butter, at room temperature
1/4 cup confectioner’s sugar
1/4 cup whole milk
3/4 teaspoon instant coffee powder
1/4 teaspoon kosher salt

For the Ganache 

8 oz bittersweet chocolate, finely chopped
1 cup heavy cream (also, full-fat coconut cream works here)
2 Tablespoons unsalted, softened butter
2 Tablespoons sugar
4 teaspoons instant espresso
pinch of salt
1/8 teaspoon vanilla

A SUPER IMPORTANT NOTE ABOUT TIMING:  Ok, so my mama made the ganache and the crumbs one day, then, the cake and the frosting a second day, then assembled it, froze it, then on the 3rd day we ate it. You can give yourself even more time as the cake will freeze for like 2 months, and the crumbs keep for several weeks. AT THE VERY LEAST, give yourself 2 days, as you’ll need about 15 hours to freeze and thaw it before serving.

To Make the Ganache

Place chocolate in small heatproof bowl. Set aside.

In a medium saucepan, heat cream, butter, sugar, espresso, salt, and vanilla over medium heat until the butter is melted and combined. Pour the hot liquid over the chocolate and let stand until the chocolate is particularly melted, 3-5 minutes.

Using a rubber spatula, stir chocolate until it is fully melted and smooth, let it cool, then pour it into a tupperware container and let it stand at room temp for one hour or until the mixture is the consistency of frosting. It will keep in the fridge for a few days while you make the other cake pieces.

To make the crumbles

Preheat the oven to 350 (F).
Combine 2/3 cup flour, 1 teaspoon cornstarch, 1/2 cup granulated sugar, 2/3 cup cocoa powder, and 1 teaspoon kosher salt in the bowl. You can use a mixer or your hands here, but mix everything together.

Add 6 tablespoons melted unsalted butter and mix until the mixture starts together in small beads or clusters.

Spread the clumps on a sheet pan (ideally lined with parchment paper)  Bake for 20 minutes,   breaking them up occasionally.

The crumbs wills till be kinda moist at this point but will get harder as they cool. Store them in a tupperware container until you’re ready to use them. They’ll keep for several weeks in the fridge.

For the Cake:

Combine your sugars and butter in the bowl of an electric mixer and mix for 2-3 minutes until fluffy.

On low, pour in 1/2 cup buttermilk, 1/2 cup oil, and 1 tablespoon vanilla. Continue mixing a few minutes, until the mixture is practically white and super increased in size (like twice the size of your original fluffy butter-and-sugar mixture, and completely mixed together). Be patient, and once this is all mixed together, scrape down the sides of the bowl.

At this point, continue mixing on low and then add  cake flour,  baking powder, and kosher salt. Mix for about a minute, until your batter comes together and any remnants of dry ingredients have been incorporated. Scrape down the sides of the bowl again, to make sure you’ve incorporated everything.
Line the sheet pan with parchment and spray with cooking spray.

Pour the batter into the pan and spread it out with the back of a spoon, and then sprinkle the mini chocolate chips on top in an even layer.
Bake 30 to 35 minutes. Check the cake at 30 minutes but poking it— the cake should bounce back slightly and the center will be firm. This is a fairly dense cake. Keep baking for a few minutes if this isn’t true of your cake.
Cool the cake, and then, using your 6″ can or cake ring, cut the cake into 2 6″ rounds. You’ll have pieces that are odd and left-over. SAVE these as you’ll smash them into the bottom of your cake and these will become the 3rd layer.

For the Coffee Frosting:

In your mixing bowl with the paddle attachment, combine 1/2 cup butter and 1/4 cup confectioner’s sugar. Cream together on medium-high for 2 to 3 minutes, until fluffy.
While that’s happening, make a coffee milk by whisking together  whole milk, teaspoon instant coffee powder, and kosher salt in a small bowl or cup.

So the butter is creamed, and of course you’ll want to scrape down the sides of the bowl.

Turn on the mixer to medium-high speed and gradually, tablespoon by tablespoon, add in the coffee. Add each tablespoon separetely, so that it all incorprates well. The butter mixture will clump up and separate upon contact with the coffee milk, but don’t freak out. (I did, but then I realized I had a temperature issue. Turns out that buttercream frosting is CRAZY heat-sensitive. If your stuff is too warm, use a cold, cold wet cloth wrapped around your bowl to bring the temp down, or just keep on mixing. It will eventually all work out.)

To assemble:

Put your laminated placemat into the can (or if you’re using a fancy real cake ring or whatever, use that) and set it on a smaller round cake pan with the bottom of the can placed underneath the can, and parchment paper under that. Squish the extra random bits of the chocolate cake until it makes a bottom, round, smushed together cake layer. Add a layer or ganache (1/3), a layer of frosting (1/3), and then a layer of crumbs (1/3). Press down firmly with a piece of parchment paper so the crumbs adhere well. Add the next cake layer and repeat. Repeat a 3rd time. Voila!

Freeze the cake for AT LEAST 12 hours before serving, and then take it out to thaw in the fridge for about 3 hours (so 15 hours total). Slice into wedges and serve!