In a large bowl, whisk sugar with the egg yolks until thick, foamy and pale.
Pour the mascarpone into themixture and starting with a fork, whisk until all lumps are completely melted.
Add egg whites heavy whipped, and gently pour it into the mascarpone cream.
In a rectangular dish spread the mascarpone cream (1/3of the entire quantity). Line with all of the ladyfingers previously soaked in coffee, one by one. Transfer the rest of the cream spreading it over the ladyfingers.
Sprinkle the whole surfacewith cocoa powder (just before you serve it, if you like dusty effect). Refrigerate for a day or at least 3 hours (following the tips as mentioned above, in the paragraph about Ladyfingers).