caster (superfine granulated) sugar 220g (8 oz)
vanilla extract half teaspoon
eggs 4, plus an extra yolk
double cream 250ml (9 fl oz)
soured cream 150ml (5 fl oz)
cornflour 30g (1 oz)
sea salt a generous pinch
1 Set the oven at 220°C (425°F). Line the inside of a high-sided 20cm (8”) springform cake tin entirely with baking (parchment) paper, making sure you bring it up the sides. It will pucker around the edges, but no matter. Place a pizza stone or baking sheet in the oven to heat up.
2 Put the cream cheese and caster sugar into the bowl of a food mixer and beat for a few seconds until mixed. Grate the lemon zest into the cheese, then add the vanilla extract.
3 Break the eggs into a small bowl, add the extra yolk and beat lightly with a fork to combine the yolks and whites. Introduce the eggs to the cream cheese, beating at slow speed, then pour in the double and soured creams. Push the mixture down the sides of the bowl with a rubber spatula and briefly continue mixing. At this point it may look too liquid but worry not.
4 Stir in the cornflour and salt, making sure it is thoroughly combined, then pour the mixture into the lined cake tin. Slide carefully into the oven, place on top of the hot stone or baking sheet and bake for 45 minutes, until the cake has risen a little and its surface is dark brown. The centre may quiver when shaken. A thoroughly good thing.
6 Now turn off the heat and leave the cake to settle for a further 10 minutes. Remove the cake from the oven and leave to cool, then place, still in its tin, in the fridge.
7 When completely cold, remove the cheesecake from its tin and serve in thick slices, perhaps with a small dish of extra soured cream.