Take 4 tablespoon water in a small pan and warm it and add Gelatin or Agar agar and dissolve it properly.
Extract Pulp from mangoes and mix it with the mango juice.
Take the mixture in a deep pan and cook in low flame for about 10 minutes or till the mixture turns translucent.
Add powder sugar and cook for another 7-10 minutes in low flame and then add dissolved Gelatin / Agar agar.
Take out the mixture from flame and cool it for around 10 minutes.
Pour it over the cheesecake and spread properly.
Refrigerate till the Jelly set.