Separate the eggs and beat the egg whites until stiff, then set aside. Add the mascarpone and powdered sugar to the egg yolks and mix briefly and slowly with a hand mixer or stand mixer, just until everything is combined.

Gently fold the beaten egg whites into the cream. Then, transfer half of the cream into a separate bowl and carefully fold in the Nutella until smooth.

Add the Amaretto to the espresso. Drizzle half of this mixture over the ladyfingers and arrange them on the bottom of the baking dish.

Spread the Nutella-mascarpone cream over the cookies and smooth it out. Soak the remaining ladyfingers in the espresso mixture, place them on top of the Nutella cream, and then spread the remaining mascarpone cream over them, smoothing the surface.

Cover the tiramisu and refrigerate for at least four hours.

Remove the tiramisu from the refrigerator, dust with cocoa powder, and sprinkle with hazelnut brittle.