Moka Dupont from Baking Chez Moi and Rachael Ray Magazine: The (icebox) cake you should make this weekend
from Baking Chez Moi, by Dorie Greenspan (Houghton Mifflin Harcourt, 2014)
Makes 8 servings
1 large, very fresh egg, preferably organic (it will not be cooked)
1 stick (8 tablespoons; 4 ounces; 113 grams) unsalted butter, at room temperature
1/2 cup (100 grams) plus 1 tablespoon sugar
3 ounces (85 grams) bittersweet chocolate, melted and cooled
1/2 cup (120 ml) hot espresso (made fresh or with instant espresso powder)
24 Petit Beurre (or Thé Brun) cookies (one 7-ounce/198-gram package)
Grated chocolate, for decoration
Before you start assembling the cake, decide on the size you want. I make a slender cake that’s 2 cookies wide (I place the cookies end to end) and 4 cookies long. This is how Mme Dupont did it, but you can make a tall tower or small individual cakes. Choose a plate on which to both build and serve the cake, and cut four strips of parchment or wax paper that you can use to protect the plate from errant frosting.
To make the buttercream frosting, separate the egg, putting the yolk in a cup and the white in a small bowl. Whip the white with a whisk until it holds soft peaks—a short but strenuous exercise (you can use a mixer if you prefer). Give the yolk a quick whisking, just to break it up. Set the eggs aside for the moment.
Put the butter in a small bowl and beat it with a flexible spatula until smooth. Add ½ cup of the sugar and beat until it’s thoroughly incorporated. Whisk the egg white again, pour the yolk over the white, and give them both another quick whipping with the whisk, then add them to the bowl, stirring to blend. Pour in the melted chocolate and, stirring and folding, mix until the frosting is homogenous. This buttercream is not meant to be perfectly smooth. Taste it, and you’ll feel sugar grains on your tongue—that’s the way it’s meant to be.
Dissolve the remaining 1 tablespoon sugar in the hot espresso and pour the espresso into a wide, shallow bowl.
One by one, dip the cookies into the espresso: Drop a cookie into the espresso, count 3 seconds, flip it over, count 3 seconds more and place it on the serving plate with one edge on the edge of the protective paper or wax strips. Continue until you have your first layer of cookies in place.
Using a small offset spatula or a table knife, spread one third of the buttercream over the cookies, working the cream to the edges of the cookies. Build two more layers of dunked cookies and smoothed buttercream; if you’d like, you can reserve a little of the buttercream and use it to cover the sides of the cake, but I leave them bare and ruffly because I think they’re pretty that way.
Top the last layer of buttercream with grated chocolate. Refrigerate the cake for at least 3 hours before serving; when the frosting is set, carefully pull away the paper strips.
Storing: The cake can be kept in the refrigerator for up to 3 days or wrapped airtight and frozen for up to 2 months; defrost in the wrapping.
(Photograph by Alan Richardson)