Boil the cleaned apricots for 5 minutes in boiling water to soften. Drain and blend them, then add the sugar.
Separately, mix the yolks with the powdered sugar, alternately add the melted butter, flour and crushed biscotti. Mix well with a mixer, add the puree and stir some more. Finally, carefully add the beaten egg whites and stir gently with a wooden spoon.
Pour the mixture into a greased oven dish and bake for 30 minutes in a moderate oven. Allow the finished cake to cool and then decorate it with cream rosettes. Optionally, sprinkle it with powdered sugar.