Separate egg whites and yolks into two large bowls.

Beat egg yolks while gradually adding sugar until smooth and pale.

Gently fold mascarpone cheese into the egg yolks.

In a separate bowl, beat egg whites until stiff peaks form.

Gently fold the beaten egg whites into the mascarpone cheese mixture.

Refrigerate the mixture until ready to assemble the tiramisu.

Brew espresso (or strong coffee). Combine the espresso with coffee liqueur.

Dip ladyfingers briefly into the coffee mixture.

Layer the soaked ladyfingers in a pan.

Spread half of the mascarpone cheese mixture evenly over the ladyfingers.

Repeat the layer of ladyfingers dipped in coffee mixture.

Spread the remaining mascarpone cheese mixture evenly over the top.

Dust the top with unsweetened cocoa powder using a fine sieve.

Cover with plastic wrap and refrigerate for at least one hour, preferably overnight.