Start by lining the base and sides of a loose bottomed cake tin with non-stick paper. Mix together the crushed biscuits and melted butter and press into the base of the cake tin. For the filling, place the ricotta, orange zest and icing sugar into a food processor and blitz together for 5-10 seconds till smooth. Stir in the chocolate chips and whipped cream and spoon over the biscuit base. Smooth out and chill for 3 hours or overnight. When ready to serve, remove from the tin and place onto a serving plate. Spread over the melted biscoff and decorate the top with the broken cannoli shells. Dust with icing sugar and serve.