For the Umbrian crescionda cake, place the amarettini cookies in a freezer bag and crumble finely with a rolling pin, or hammer.
Separate the eggs and whisk the yolks together with the sugar to a light, fluffy cream. Stir in the grated chocolate, milk and liqueur and gradually add the cookie crumbs and flour.
Beat the egg whites with a pinch of salt until stiff and gently fold into the batter.
Pour the liquid batter into a buttered and floured cake pan and bake in a preheated oven at 180 °C for about 60 minutes.
Sprinkle the Umbrian crescionda cake with powdered sugar before serving.