Put the milk powder in pure water.
Stir well with egg.
Pour into the milk pot, heat it on low heat, and use a scraper to keep the bottom of the bottom.
Small fire, must be a small fire! Be patient, keep licking, until you are screaming.
From the fire, you can see that it is very thick on the scraper. It is very hot now, and it will be thicker when it is cool.
Look at the cool finished product, is it very thick.