Ingredients
1 1/2 cups finely ground chocolate wafer cookies (8 ounces; about 35 cookies)
4 tablespoons unsalted butter, melted
1/2 cup plus 2 tablespoons sugar
4 large egg yolks, room temperature
4 1/2 teaspoons good-quality instant espresso powder (such as Medaglia d’Oro)
Pinch of salt
1 1/2 pounds mascarpone cheese, room temperature
1 1/2 teaspoons pure vanilla extract
12 ounces hard torrone (Italian nougat), cut into 1/4-inch pieces
1/2 cup heavy cream, chilled
Preparation
Stir together cookie crumbs, melted butter, and 3 tablespoons sugar in a medium bowl; set aside.
Put egg yolks, 1/4 cup sugar, the espresso, and salt in the heatproof bowl of an electric mixer. Set bowl over a pan of simmering water; whisk until thick, about 2 minutes. Transfer bowl to an electric mixer fitted with the whisk attachment; beat on medium speed 2 minutes. Stir in mascarpone and vanilla by hand until smooth. Stir in torrone; set aside.
Beat cream with remaining 3 tablespoons sugar in a clean mixing bowl until soft peaks form. Fold the whipped cream with a rubber spatula into mascarpone mixture. Refrigerate.
Line a 10-by-5-by-3-inch loaf pan with plastic wrap and parchment paper, leaving an overhang on sides. Pour one-third of mascarpone mixture into lined pan; even layer with an offset spatula. Evenly top with half of the crumb mixture; press crumbs gently. Repeat to make a second layer of mascarpone mixture and crumbs. Top with remaining mascarpone mixture. Loosely fold over parchment and plastic wrap. Freeze 3 hours or overnight.
To serve, let cake stand at room temperature 10 minutes. Set loaf pan in a larger pan; pour cold water into pan to reach three-quarters up sides of loaf pan. Let stand 10 seconds. Holding parchment, lift out cake. Invert onto a plate; peel off plastic and parchment. Let stand 10 minutes more before serving.
