Beat egg yolks with sugar until thick and light lemon color. Remove from mixer and add mascarpone cheese and lemon rind, folding.
Whip egg whites until thick and add to cheese mixture, folding carefully.
Combine espresso and coffee liquor in a large shallow dish and dip both sides of ladyfingers.
Arrange ladyfingers in the bottom of a rectangular glass serving dish. Cover with half of the cheese cream. Repeat a second layer of ladyfingers dipped in coffee and spread remaining cheese cream on top. Refrigerate.
If possible prepare this dessert the day before and keep it in the refrigerator.
Before serving sift cocoa or sprinkle shredded chocolate on top.