Preheat the oven to 150°C.
Melt the butter gently in a heavy-based pan.
Process the digestive and ginger biscuits in a food processor until they form fine crumbs.
Line a 24cm spring-form cake tin with greaseproof paper and brush the base with melted butter.
Mix the remaining melted butter with the biscuit crumbs in the processor.
Press the crumbs into the tin base with a spoon until level.
Bake the base for 10-15 minutes until lightly browned and let cool for five minutes.
Whisk cream cheese, 150ml cream, caster sugar, eggs, and lime zest until smooth.
Pour the filling onto the cooled base.
Bake for one hour until set, cool completely, then chill in the fridge for one hour.
Remove the cheesecake from the tin and place on a serving plate.
Peel and thinly slice the pineapple using a mandoline.
Toss the pineapple slices with the pulp and juice of the passion fruits.
Whisk 300ml cream with icing sugar until soft peaks form.
Spread the cream over the cheesecake, top with the fruit mixture, and dust with icing sugar.