Whip the cold heavy cream in a large bowl on medium-high speed until stiff peaks form, about 3 to 4 minutes.

In a separate bowl, whisk the mascarpone, sweetened condensed milk, vanilla, salt, and cooled espresso until smooth. Gently fold this into the whipped cream until no white streaks remain.

Crumble the ladyfingers into grape-sized pieces. In a loaf pan, spread one-third of the cream, scatter half the ladyfingers and a dusting of cocoa, repeat layers, then top with remaining cream and a generous cocoa dust.

Cover and freeze until firm, at least 6 hours. Scoop and serve, softening at room temperature for 5 minutes if needed.