Put the pot on low heat and stir constantly until the composition thickens and almost starts to boil, be careful not to be lumpy - better mix with a fork.
If you use a heat-resistant glass dish, put it on the steam bath, and mix well until it starts to boil. Just make sure it lasts longer here, with the kettle it's faster.
When ready, remove from the heat and let cool for 5-10 minutes.