Boil water in a saucepan, place a bowl over it. Make sure the bowl doesn't touch the boiling water.
Add the butter.
Mix with a spoon until it melts
Then start adding the icing sugar little by little, keep mixing
Once you are done with icing sugar add the milk powder
Mix it well to avoid lumps
Add vanilla essence and salt
Mix and then remove from the heat
The consistency should be flowing
Now spoon the mixture into the chocolate mold
Refrigerate at least for an hour.
If you touch them, they should not stick and should be firm.