Preheat your oven to 160°C (325°F). Blend digestive biscuits until fine crumbs. Melt butter and mix with crumbs. Press into a 9-inch springform pan. Bake for 10 minutes, then cool.

Beat cream cheese until smooth. Gradually add caster sugar, sour cream, vanilla extract, and salt, mixing until silky.

Add eggs one at a time, mixing gently after each addition to keep the filling smooth.

Pour filling over the cooled crust and bake for 50-60 minutes until edges puff and center jiggles slightly. Cool at room temperature.

Cool in the pan for 10 minutes, then refrigerate for at least 4 hours or overnight.

Before serving, sprinkle granulated sugar on top and caramelize with a torch until golden brown.