Prepare a 9-inch springform pan by lining the base with baking paper and lining the sides with parchment paper.
Crush the biscuits into fine crumbs using a food processor.
Mix the biscuit crumbs with melted butter and sugar until evenly combined.
Firmly press the mixture into the bottom of the prepared pan and refrigerate.
Sprinkle gelatin over cold water and let it bloom for 5 minutes.
Microwave the gelatin in short intervals, stirring until completely dissolved. Allow it to cool slightly.
Blend the mango flesh into a smooth puree. Reserve ¾ cup for the topping.
Add cream cheese, whipping cream, caster sugar, remaining mango puree, and dissolved gelatin to a food processor. Blend until silky smooth.
Pour the filling over the chilled biscuit base and smooth the top.
Refrigerate the No Bake Mango Cheesecake for at least 3 hours until firm.
Prepare the mango jelly by blooming and dissolving the remaining gelatin. Mix it with the reserved mango puree and lemon juice.
Gently pour the jelly over the cheesecake and spread evenly.
Refrigerate overnight or for at least 12 hours.
Remove from the pan and decorate with whipped cream, fresh mango cubes, and passionfruit before serving.