In a large mixing bowl, combine dulce de leche and mascarpone cheese, mixing until smooth.
In a separate bowl, whip heavy cream until stiff peaks form, then fold into the dulce de leche mixture.
Dip each ladyfinger into the espresso briefly, ensuring they are soaked but not soggy.
Layer half of the soaked ladyfingers in the bottom of a dish.
Spread half of the dulce de leche mixture over the ladyfingers.
Repeat with remaining ladyfingers and dulce de leche mixture.
Cover and refrigerate for at least 4 hours or overnight.
Before serving, dust the top with cocoa powder.
