Mocha Chiffon Cake

Dear Coffee,

I first met you when I was five or so, when my mom used to put a teaspoon of decaffeinated instant coffee in my glass to get me to drink hot milk. It shouldn't have worked--what five-year-old would prefer to take her milk with coffee?--yet it did. Maybe it's too much to say that it was love at first sight, but it was close. My interest was piqued. You were slightly bitter, yet warm and comforting. Somewhat exotic, yet cozy.

I flirted with you over the next few years, in Starbucks frappuccinos, ice cream, yogurt, when I'd add a spoonful of instant coffee to my hot chocolate. But soon the romance began in earnest. I began to see you regularly, almost every morning. At first I thought you to be a little overpowering, and would dump lots milk and sugar in my mug, but eventually I found them to be superfluous. Now I take it black, and it's just you and me.

You've come to me in many guises: in the eh-coffee in the dining halls, reheated several times as I study in the evenings, the coffee grabbed from JP Licks while I work at the school paper late into the night, the bitter, rich espresso from the moka at home, the slightly too strong instant coffee made in the dorm in the mornings, the frothy macchiatos in Italy, the black coffee boasted to be from exotic locations served in giant vat-like mugs on the second floor of the Starbucks in the Harvard Square.

There's definitely been rocky moments between us, headaches from spending too much time with you and feeling jittery and cups of sour, inky liquid pretending to be you.  But it's been worth it in the end.

So this cake is in many ways a love letter to you, a sweet three-layer, cream-filled, macaron-topped love letter.

You're in almost every aspect of this cake--from the chocolate-coffee chiffon cake layers, the coffee pastry cream filling, the coffee-flavored whipped cream frosting, the coffee syrup brushed on the macaron shells. However, you know better than to scream your presence. The coffee flavor is only strong enough to be sweet, rich and comforting.

I think this cake does you justice. It requires a bit of time and work, but it's definitely worth it. It is delicious, thanks to you. The light, airy cake pairs perfectly with the smooth, rich pastry cream sandwiched between  the layers and the sweet and fluffy whipped cream topped with mocha hazelnut macarons.

And it's perfect when enjoyed with a cup of, yes, coffee.

It's been a while since you've been able to keep me up at night. At this point I know you too well for the caffeine to really affect me. But I like you as much as I ever did, for your strong and comforting aroma that weaves its way into a room, your slightly bitter tang, your warmth in a large mug on a cold day. That's what this cake captures.

And so, to coffee, from Caroline, with love.

Notes on making the cake:

The cake itself is a chocolate-coffee flavored chiffon cake. I'd describe chiffon cake as a cross between a yellow cake and an angel food cake. It gets its fluffiness from beating the egg whites in a meringue, like angel food cake, but it has more flour and fat. This recipe on the denser side for a chiffon cake - it has a higher ratio of flour to eggs than most recipes. While it does require beating and folding in the egg whites, chiffon cake isn't too hard--it just requires an electric mixer and some patience.

While the macarons are definitely optional, they do make a cute addition to the cake. These are plain macaron shells brushed with a coffee-flavored syrup and filled with Nutella. (I love the coffee-hazelnut combination, and the coffee-hazelnut-chocolate combination is even better). You can find my step-by-step photos for making macarons here

I'd suggest making this cake over two days, making the chiffon cake, pastry cream, and macarons on the first day, and making the whipped cream and assembling the cake on the second day.

Mocha Chiffon Cake

Click here fore the printer-friendly recipe

Cake recipe adapted from Food 52, pastry cream filling adapted from The Kitchn and inspired by the Pierre Hermé Pastries cookbook. Macarons adapted from Bravetart.

4 eggs, separated
⅛ teaspoon cream of tartar
1 cup granulated sugar, divided
⅓ plus 1 tablespoon vegetable oil
1 teaspoon vanilla extract
2 cups plus 2 tablespoons cake flour
3 teaspoons baking powder
1 teaspoon salt
2 tablespoons cocoa powder
½ cup espresso, or strongly brewed coffee
½ cup whole milk

Coffee pastry cream
1 ½ cup whole milk
4 egg yolks
⅓ cup sugar
¼ cup flour
¼ teaspoon salt
2 teaspoons vanilla extract
1 tablespoon instant coffee
1 - 2 tablespoons hot water

Mocha Hazelnut Macarons (Optional)
For the shells:
2 oz. (58 g) Almond Flour or blanched Almonds
4 oz. (115 g) Powdered sugar
1.25 oz. (36 g) Granulated sugar
¼ teaspoon (1 g) Salt
2.5 oz. (72 g) Egg whites (about 2 eggs)

For the Filling
2 tablespoons instant coffee
2 - 3 tablespoons hot water
2 teaspoons honey
¼ cup Nutella

Coffee whipped cream
1 tablespoon instant coffee
1 - 2 tablespoons hot water
1 ½ cup heavy whipping cream
⅔ cups powdered sugar

Cake Assembly
¼ cup butter, softened
3 tablespoons powdered sugar

Make this cake over the course of two days, making the cake itself, the pastry cream, and macarons (if you’re using them) on the first day and making the whipped cream and assembling the cake on the second day.

For the Cake
Preheat the oven to 350 degrees Fahrenheit.
Whip the egg whites in a clean glass or metal bowl on medium speed until frothy. Whisk in the cream of tartar. While whisking, gradually add ½ cup of granulated sugar. Whip the egg whites on high speed until they form stiff, glossy peaks. Set aside.

Whisk together the egg yolks, vegetable oil, the remaining ½ cup of sugar, and the vanilla. In a separate bowl, whisk together the flour, salt, baking powder, and cocoa powder.

Mix together the coffee and milk. Mix in ⅓ of the flour mixture into the egg yolk/oil/sugar mixture. Mix in ⅓ of the coffee/milk mixture into the egg yolk mixture. Continue alternately adding flour and coffee until they are both all incorporated.

Fold in about ⅓ of the egg white mixture to the batter to lighten it. Fold in the rest of the egg whites.

Pour the batter into a 9-inch round ungreased springform cake pan. Bake the cake for 30-35 minutes, or until a toothpick inserted in the center of the cake comes out clean. Let cool.


For the Coffee Pastry Cream
Place the milk in a saucepan and bring to a simmer on the stove.
In a separate bowl, whisk the egg yolks with the sugar until they turn a pale yellow. Whisk in the flour and salt.

While whisking constantly, slowly drizzle in about ⅔ of the hot milk into the bowl with the egg yolks. Pour the egg yolks/milk mixture back into the saucepan and cook it over medium-low heat stirring constantly. The pastry cream is done when it becomes a thick paste and large bubbles begin to pop through the surface. Take the saucepan off the stove and whisk in the vanilla extract.

In a small bowl, mix together the instant coffee and 1 tablespoon hot water. If the mixture is too thick and the coffee doesn’t completely dissolve, add another tablespoon of water. Whisk the coffee mixture into the pastry cream.

Allow the pastry cream to cool, then cover it with a piece of plastic wrap placed directly over the surface of the cream so that it does not form a hard crust. Refrigerate several hours, preferably overnight.


For the Macarons
 If you’re using whole almonds, you’ll need to grind them. Place the almonds in a food processor and roughly grind them. It doesn’t need to be too fine, but there shouldn’t be any large chunks. Add in two or three tablespoons of powdered sugar and continue grinding the almonds until they are very fine. Add the rest of the powdered sugar and grind for another 15-30 seconds.

Make the meringue. Mix together the granulated sugar and salt. In a very clean bowl, begin beating the egg whites on medium-low speed until frothy, about 1-2 minutes. Increase speed to medium, and gradually add the granulated sugar-salt mixture, and beat until soft peaks form, about 2-3 minutes. Increase speed to high, and beat until the meringue is very stiff and shiny, about 2-3 minutes.

Hold a mesh strainer over the meringue, and sift the almond mixture over the meringue. Return any pieces that don’t pass through the strainer to the food processor, and grind them some more, and sift them again. There may still be a few bits that are too big (less than a tablespoonful); just add them to the meringue.

Begin folding the dry ingredients into the meringue. Be sure to scrape the edges of the bowl. When done, the batter should be think, but somewhat fluid. Do the ribbon and/glop test to check.

  • Ribbon test: hold a spatula-full of batter over the bowl, and it should fall into the bowl in a thick ribbon. The ribbon should re-incorporate into the batter within about 30 seconds.
  • Glop test: drop a spoonful of batter onto a plate. The peak should smooth out within 10 seconds.

Line a cookie sheet with parchment paper or Silipat.
Put the batter into a pastry bag with a round tip about ¼-inch wide. Pipe out 1-inch wide circles, leaving around 1 inch between circles.
Rap the baking sheet against a counter or tape several times to release any air bubbles trapped in the batter. You should see bubbles rise to the top and pop.

Preheat oven to 300 degrees Fahrenheit. Allow the batter to rest in open air until the tops are set; when you lightly touch the circles with a finger, no batter sticks to it.

Put the macarons in the oven and bake for 18-20 minutes, until the cookies can come cleanly off the parchment paper, and the insides are done. (They should be slightly damp on the inside, but not wet and sticky.) Let the shells cool completely.

Mix together the instant coffee, honey, and 2 tablespoons hot water. If the coffee doesn’t dissolve completely, add another tablespoon of water. Brush the bottoms of all the macaron shells with the coffee syrup. Fill the macarons with Nutella. Place about a teaspoon of Nutella on a macaron shell and place another shell on top.
Refrigerate the macarons overnight.

For the Coffee Whipped Cream
Place the mixing bowl you will be whipping the cream in and the whisks in the freezer for 30 minutes. In a small bowl, mix together the instant coffee and 1 tablespoon hot water. If the mixture is too thick and the coffee doesn’t completely dissolve, add another tablespoon of water.

Whisk the heavy cream while gradually adding in the powdered sugar. Continue whisking until the cream form stiff peaks.Add the coffee mixture to the cream and whisk until just combined.

For Assembling the Cake
Run a knife along the edge of the cake, to help remove if from the pan. Remove the springform ring from around the cake. Gently saw the cake away from the bottom of the springform pan.

With a large, sharp knife, cut off the domed top of the cake so that it is flat. Cut the cake into three even layers.

Whisk together the butter and powdered sugar. Whisk in the coffee pastry cream you made. Fold in about ½ cup of the coffee whipped cream you made.
Place one cake layer on cake stand. Evenly spread on about half of the pastry cream mixture. Place another cake layer on top of cream, and spread the remaining pastry cream on the cake. Top with the remaining cake layer.

Evenly spread whipped cream on the sides and top of the cake. Pipe decorations with the whipped cream. Decorate the top of the cake with macarons and coffee beans, if desired.

Slice, serve, and dig in!