aside. In a separate bowl blend together the 4 egg yolks, 2 tbsp of the caster sugar and the flour. In the meantime, heat the milk in a saucepan just until it begins to boil and then stir gradually into the egg yolk mixture. Transfer this liquid back into the saucepan and simmer gently, stirring continuously, over a medium heat until the mixture starts to thicken. Stir in the remainder of the Amaretto liqueur. Remove from the heat. In a copper or glass bowl, whisk the 5 egg whites until soft peaks form. Whisk in the remaining sugar, 1 tbsp at a time and continue to whisk until the egg whites stand in stiff peaks and hold their form. Stir  of the whisked egg whites into the milk mixture with a metal spoon or a rubber spatula. Carefully fold the remainder of the egg whites into this mixture, turning the mixture over and over. Transfer half of the mixture into the greased souffl dish, cover with the amaretti biscuits and finish off with the rest of the egg white mixture. Place the souffl dish into the preheated hot oven and bake for 20 minutes until the souffl has risen 2 inches above the dish and is crisp and golden brown on top. Remove from the oven and dust with the icing sugar. Serve immediately with a little cream or ice cream on the side.