Make jelly as per packet direction and chill in fridge till ready.
Now take custard powder in a bowl, add little milk and mix well. Set aside.
Take sugar and milk in a saucepan and heat till it gets hot.
Add the custard mix and cook on a low heat till it is thickened. Now pour it in a bowl, cover with plastic wrap make sure the wrap touches the custard. Chill in fridge for 1 to 2 hours.
When assembling, take jelly and custard from fridge and give everything a good mix.
In a serving glass, take some custard and top with jelly.