Step 1: Cut
Cut each potato into small pieces.
Step 2: Boil
Boil a pan of water and add the potato for about 3 or 4 minutes. Add some salt if you like. Don't let the potato become mushy and lose flavour.
Step 3: Cool
Cool the potato quickly by spooning the pieces into a pan of iced water, or alternatively run under a cold water tap. Leave in the iced water for as long as you boiled them - about 4 minutes.
Step 4: Dry
Take the pototo out of the water and allow to dry for a few minutes on a plate, work surface, tea towel or paper towel.
Step 5: Freeze
Pop the potato pieces into a freezer bag. Push the air out of the bag and roll it up to seal. If you like, stick a note on with the date. The potato should keep for many months.