Line an 8x8 inch square pan with parchment paper, ensuring an overhang on two sides for easy removal.

Combine crushed biscuits and melted butter in a bowl; press firmly into the bottom of the prepared pan and refrigerate.

In a small ramekin, sprinkle gelatin over the cold water and let it bloom for 5-10 minutes.

In a large mixing bowl, beat the cream cheese and powdered sugar until smooth and aerated.

Whisk the mango puree and passionfruit pulp into the cream cheese mixture until fully incorporated.

Gently heat the bloomed gelatin in the microwave for 15-20 seconds until completely dissolved; stir a small amount of the fruit mixture into the gelatin to temper it, then stir the gelatin into the main bowl.

In a separate chilled bowl, whip the heavy cream to stiff peaks.

Gently fold the whipped cream into the mango and passionfruit mixture until no white streaks remain.

Pour the filling over the biscuit base and smooth the surface with an offset spatula.

Refrigerate for at least 4 hours, or until the filling is firm and set, before lifting from the pan and slicing into 12 bars.