Crush the cannoli shells, reserving 2 for garnishing later on. Mix in the melted butter and press the cannoli mix into the bottom of a lined 8 inch spring form cake tin lined with cling film using the back of a spoon to flatten. Chill for 30 minutes. Meanwhile, soak the gelatin leaves into the juice of an orange and heat up in a saucepan or microwave to dissolve. Whisk the ricotta till smooth and creamy then stir in the icing sugar, orange zest, chocolate chips and melted gelatin mixture. Next, whip the cream and gently fold in. Spread the mixture evenly on the cannoli base and allow to set and chill for at least 2 hours. When ready, remove from the cake tin and place onto a serving dish. Decorate the top with reserved 2 crushed cannoli, orange zest, chocolate chips and pistachios.