How to cook
Peel the sweet potatoes, chop them finely and boil until softened with the lid closed. Mash them.
Mix the eggs with the sugar and milk. Heat them in a water bath until thickened.
Cool and mix them with the potato puree. Beat the cream with the rum and add it to the potato mixture.
Put it in a suitable plastic or metal container and freeze for 6 hours in the freezer, stirring every 2 hours.