Chop up the marzipan mixture and heat it with the powdered sugar and milk over medium heat, stirring constantly. Remove the hot, but not boiling, milk from the stove and stir until smooth with the hand blender. There must be no more lumps.
Pour the marzipan milk into a cool container and stir in the aromas (bitter almond aroma and rose water). Cover and chill for 1 hour.
Before pouring into the ice cream machine, whip the mixture briefly and vigorously. Then fold in the cream. Freeze for 20-30 minutes.