1) In a microwavable bowl or jug, stir in the custard powder, sugar and a little bit of cold milk.
2) Add in the remaining milk. Stir to mix well.
3) Cook the mixture for about 7 minutes.
4) Stir with a spoon every couple of minutes.
5) The Custard Sauce is done when the mixture turns thick and creamy after cooking.
6) Serve the Custard Sauce over cakes, fruits etc.