Lay out enough ladyfingers in the bottom of the serving dish to cover the base entirely, chopping any up as necessary. Set aside the same amount of ladyfingers (chopped as required) for the second layer. Remove from the dish and set aside
Whip the egg whites until fluffy
Use the same beaters to whip the egg yolks and sugar until very thick, creamy and pale - around 3-4 minutes. They are whipped sufficiently when a trail remains for a few seconds after the mixture falls off the whisk (this is the ribbon stage)
Stir the orange zest through
Stir the mascrapone to loosen it, then add to the egg yolk mixture and beat in until just combined (either by hand or using electric beater on a low speed). Take care not to overbeat as the mascarpone could curdle. If using electric beaters, try beating in 15 second bursts to ensure is is beaten just sufficiently
Gently fold the whipped egg white in using a large metal spoon
Mix the coffee, amaretto and orange juice together in a shallow bowl then dip a ladyfinger into the coffee then flip over to coat the other side (dip for around 4 seconds in total)
Place the ladyfinger in the base of your serving bowl. Continue with more ladyfingers until the base is covered
Top with half of the mascarpone mixture
Add another layer of ladyfingers, dipping them in the coffee mixture as before
Spoon the remaining mascarpone mix over the top, smooth it out, cover and refrigerate for at least 6 hours but preferably overnight
When ready to serve dredge in sifted cocoa powder and (optional) grated chocolate