Crush the digestive biscuits and mix with melted butter.
Press the mixture into a lined 20cm springform tin and chill for 30 minutes.
Dissolve the gelatine in warm water and allow it to cool slightly.
Beat the cream cheese and caster sugar until smooth.
Add the orange zest, orange juice, vanilla extract, and passion fruit pulp.
Whip the double cream to soft peaks and gently fold it into the filling.
Stir in the dissolved gelatine until fully combined.
Pour the filling over the chilled biscuit base and smooth the top.
Refrigerate for at least 4 hours or overnight until fully set.
Decorate with passion fruit pulp, orange zest, and fresh orange slices before serving.