Take a proper amount of purple potato steamed, or heat it in a microwave oven. Personally recommend the latter, it is faster, and will not make the pot into color ~
Cut the steamed purple potato into small pieces in milk.
Heat over low heat until the milk is boiling, then the milk will turn into a beautiful purple!
The amount of purple sweet potato and milk is based on personal taste. If the amount of purple potato is too much, you can make purple potato milk mud~
Purple sweet potato must be steamed first and then put in milk, otherwise you will find that the milk produced by raw purple potato will be a strange blue, 嘿嘿~~