In a mixing bowl, beat the heavy cream, mascarpone cheese, powdered sugar, and vanilla extract until smooth and fluffy.
Dip each ladyfinger into the hot chocolate and layer them in a serving dish.
Spread a layer of the mascarpone mixture over the soaked ladyfingers.
Repeat the layers until all ingredients are used.
Drizzle melted dark chocolate on top and dust with cocoa powder.
Chill for at least 4 hours before serving.