Blend or crush the amaretti and digestive biscuits to a fine crumb.
Mix them with the cream cheese until you get a dense consistency that stays together but isn't too wet and sticky. Add it gradually to get the right amount.
Roll the mixture into small balls, pierce with a wooden skewer and chill in a fridge on a tray for at least 30 minutes. If you're in a hurry, pop them in the freezer.
Melt the white chocolate by placing it in a bowl above (but not touching) a saucepan of boiled water, or melt in the microwave.
Dip the cheesecake balls into the melted white chocolate and then immediately into more crushed amaretti biscuits before chilling until set either in the fridge or freezer...depending on how soon you want to eat them.