Moka Dupont: A French Icebox Cake

Step 1

Before you start assembling the cake, decide on the size you want. I make a cake that’s 4 cookies wide, 4 cookies long and 4 layers high. Choose a plate to build and serve the cake.

Step 2

Make the buttercream frosting: Put the butter in a small bowl, and beat it with a flexible spatula until smooth. Add 1/2 cup sugar, and beat again with the spatula until it’s thoroughly incorporated. Separate the egg, putting the yolk in a cup and the white in a small bowl. Whip the white until it holds soft peaks using a mixer or, for a short but strenuous exercise, a whisk. Give the yolk a quick whisk, just to break it up, then stir it into the white.

Step 3

Add the egg to the bowl with the butter, and using the spatula, stir and fold until blended. Scrape in the melted chocolate, then stir and fold again until the frosting is homogeneous. (It won’t be perfectly smooth.) Taste the buttercream, and you’ll feel grains of sugar on your tongue — that’s the way it’s meant to be.

Step 4

Pour the hot espresso into a wide, shallow bowl, and stir in the remaining 1 tablespoon sugar.

Step 5

One by one, drop each cookie into the espresso, count 3 seconds, flip it over, count 3 seconds more, then place the espresso-soaked cookie on the serving plate. Continue until you have your first layer of cookies in place.

Step 6

Using a small offset spatula or a table knife, spread a quarter of the buttercream over the cookies, working the cream to the edges of the cookies. Build 3 more layers of dunked cookies and smoothed buttercream. Top the last layer of buttercream with grated chocolate.

Step 7

Refrigerate the cake until the frosting is set, at least 3 hours. The cake can be kept covered in the refrigerator for up to 3 days. (Once the frosting is set, the cake could also be wrapped airtight and frozen for up to 2 months. To serve, simply let it defrost, still wrapped, in the refrigerator for about 4 hours or at room temperature for about 1 hour.)