Whip heavy cream until it reaches stiff peaks in a medium bowl and refrigerate.

In a large bowl, beat together egg yolks with 1/3 cup sugar until light in color.

In a separate bowl, beat egg whites until they reach soft peaks. Add 1 Tbsp sugar and beat until the whites are firm and glossy.

Fold the whipped cream into the egg yolk and sugar mixture, then fold in mascarpone and 1/3 of the beaten egg whites. Finally fold in the remaining egg whites.

Pour espresso into a shallow, wide-mouthed bowl. Dip each ladyfinger on both sides in the espresso and line the bottom of an 8x11" glass baking dish. Spoon over half of the mascarpone mixture over the ladyfingers and spread in a smooth layer. Continue dipping the remaining ladyfingers and arrange on top of the mascarpone layer. Spread another layer of the mascarpone on top in an even layer. Cover and refrigerate overnight.

Before serving, sift cocoa powder on top. Cut into squares and serve.