• Set an oven shelf in the middle of the oven. Preheat the oven to180°C/ 356°F
• Grease and line the base of a 10 inch springform cake tin. Wrap two layers of heavy duty foil around the bottom and side so that water from the water bath cannot get in.
• In a medium bowl, combine digestive crumbs and melted butter. Stir until well combined and the crumbs are moistened. Press the crumbs into an even layer on the bottom of the pan.
• Bake the crust in the oven for 10 minutes. Leave to cool on a wire rack while preparing the cheesecake filling.
• Reduce the oven temperature to 160°C/320°F.
• In bowl of the mixer (or using hand mixer) beat the cream cheese until smooth and creamy, slowly beat in sugar. Add the vanilla extract, lemon zest, lemon juice and salt and beat until just combined. Mix in the sour cream and corn starch. Scrape the sides of bowl as needed.
• Add whole eggs and yolk, one at a time and beat on low speed until incorporated . Do not over mix the cheesecake batter.
• Pour the cheesecake batter over the crust. Set the cheesecake pan inside another large roasting tin or tray. Pour boiling water carefully into the large baking tray to one third height of the cheesecake pan,
• Bake cheesecake for 1 hour 30 minutes. Turn off oven and leave cheesecake in oven for one hour with the door slightly ajar.
• Once the oven is cool, remove the cheesecake from the oven and carefully lift out of the water bath.
• Loosely cover the cheesecake and chill in the fridge for at least 4 hours or overnight before serving.

Raspberry Coulis

• Put all the ingredients in a food processor or use a hand blender, blitz until very smooth.
• Set a fine mesh strainer over a medium boil, Pour the puree through it, stir and strain until all the liquid is extracted. Discard the seeds.