Espresso-Mocha Icebox Cake

Start to finish: 1 hour 30 minutes | Inactive: 12 hours 30 minutes
Impresses: 12-16

Ingredients
For the chocolate coffee custard:
1¼ cups half & half
1/3 cup sugar
3 egg yolks
1½ tablespoons cornstarch
½ teaspoon kosher salt
4 ounces semi-sweet chocolate, chopped
1 teaspoon instant espresso powder
1 tablespoon unsalted butter, softened
1 teaspoon vanilla extract
1 cup heavy cream
2 tablespoons powdered sugar

For the vanilla
whipped cream:
1½ cups heavy cream
¼ cup powdered sugar
1 teaspoon vanilla extract

For the icebox cake:
1 package chocolate graham crackers
1½ cups heavy cream
¼ cup powdered sugar
1 teaspoon vanilla extract
2 ounces brewed espresso, cooled

Method
For the chocolate coffee custard: 
Pour half & half into a medium saucepan and set over medium-low heat. In a glass bowl, whisk together sugar, egg yolks, cornstarch and salt until thick and pale yellow, about 2 minutes. When half & half is steaming, pour a thin stream into the sugar and egg yolk mixture while whisking constantly to temper the eggs. Whisk until smooth before pouring mixture back into saucepan. Stir in the chopped chocolate and espresso powder.

Cook custard, gently stirring constantly, until thick enough to hold the outline of a figure 8 made with a spoon. Remove from heat and whisk in butter and vanilla extract. Pour into a clean glass bowl, cover with plastic wrap and set aside until cooled to room temperature. When custard is room temperature, whip heavy cream and powdered sugar to medium peaks. Gently fold whipped cream into the custard and set aside.

For the vanilla whipped cream:

Whip heavy cream, powdered sugar and vanilla extract to stiff peaks and set aside.

For the icebox cake:
Line a 9-by-5-inch loaf pan with plastic wrap on all sides, making sure to leave an overhang on the long sides of the pan to wrap the top of the cake.

Place a layer of graham crackers in the bottom of the pan, breaking or cutting the crackers to make them fit in an even layer. Top with a layer of chocolate custard, about 1½ cups, followed by a layer of vanilla whipped cream. Repeat the process of layering crackers, custard and vanilla whipped cream 1 more time. Top with a final layer of custard and then a final layer of cookies. Cover and refrigerate for at least 12 hours.

When ready to serve, whip the remaining heavy cream, powdered sugar, vanilla extract and cooled espresso until thick. Unwrap the cake and invert the pan on a serving platter.

Remove the pan and plastic wrap from the cake and, cover with the espresso whipped cream. Garnish with chopped chocolate to serve, if desired.