Prepare the coffee. Let it cool in a small bowl
Separate the egg whites from the yolks, put them in 2 different bowls
Whip the yolks well with a hand blender. Add 3 tablespoons of sugar, one by one
Add the mascarpone to the whipped yolk, mix well
Whisk the egg whites until stiff
When the egg whites have become stiff, add them to the freshly prepared mascarpone cream, stirring gently from bottom to top
Add one small glass of rum or liqueur to the already cooled coffe.
Take a pan, spread a first thin layer of mascarpone cream
Soak the biscuits, place a first layer on the bottom of the pan
Alternate layers of mascarpone cream with layers of ladyfingers soaked in coffee
Cover the pan with a sheet of silver paper and let it rest for a few hours in the refrigerator
Before serving, sprinkle the Tiramisù with sifted bitter cocoa