Start by making the custard, because it has to cool down.
Take Custard powder in a bowl and add some of the milk. Mix well so no lumps are formed. Set aside.
Now take the remaining milk and sugar in a sauce pan and bring it to boil, add in the custard mix and keep cooking till it gets thick.
Take it off the heat and add in vanilla. Mix well.
Pour this into a bowl and cover with plastic wrap, make sure the wrap touches the top layer of the custard so a hard skin don’t form on the custard.
Chill this in fridge till cold.
Now make the Custard filling. First take gelatin and add in cold water. Mix well. Set aside so it softens.
Take this in a a sauce pan and melt it gently till the gelatin is completely melted. Set aside.
Now take cream in a bowl and whip it till thick. Set aside.
Take mangoes in a blender, add in 3 tablespoon sugar and puree them. Set aside.
Take the cooled custard in a bowl, add in mango puree, gelatin and cream. Fold gently.
Spoon this into glasses and top with fresh mango pieces.
Chill for 2 to 4 hours and serve.