1. Preheat the oven to 150°C (130°C fan-forced). Process the biscuits until fine, transfer to a medium bowl. Stir in the butter until combined. Press the biscuit mixture evenly over the base and sides of a greased 26cm springform pan. To achieve a neat crust, press the crumb mixture firmly with
a straight-sided glass or bottle. Place the pan on an oven tray; refrigerate while preparing the filling.

2. For a smooth textured result, have the cream cheese, eggs and sour cream at close to room temperature. Beat the cream cheese, 3/4 cup of the sugar, egg yolks and cornflour in a large bowl with an electric mixer until smooth. Add the vanilla, sour cream and juice; beat until just combined.

3. Beat the egg whites in a small bowl with
an electric mixer until soft peaks form. Gradually add the remaining 1/4 cup of sugar, beating until dissolved. With a large balloon whisk, fold the egg white mixture into the cream cheese mixture.

4. Spread the filling into the biscuit base; bake the cheesecake for about 1 hour or until just set. Switch off oven, cool in oven with the door ajar — this helps to prevent the cheesecake from cracking. Refrigerate for at least 3 hours before serving.

5. Serve dusted with sifted icing sugar.

Suitable to freeze. Butter suitable to microwave.