Preheat oven to 160°C. Finely crush biscuits. In a pot, add butter and rosemary. Slowly heat butter until melted (do not boil or burn). Allow rosemary to infuse for 10 minutes before removing sticks. Add melted butter to the biscuits and combine.
Grease an oven pan (preferable dimensions: 6cm deep, 20cm round) Using a springform pan will be an advantage after baking – the cake can be more easily removed.
Press mixture over the base and sides of pan. Refrigerate for 15 minutes.
Beat cream cheese, sugar and citrus rind together until smooth. One at a time, add the eggs, beating until combined before adding the next one. Add citrus juice – beat for a few more moments. Pour mixture onto prepared base.
Place in oven and bake for 50 minutes to 1 hour – until mixture is just set. Refrigerate until cold.
Peel and cut 2 oranges. In a pan, heat sugar, 1tsp vanilla essence and add oranges. Let simmer for a few minutes – do not let sugar burn.
Top cheesecake with a spoonful of orange syrup mixture, and enjoy!