For the base
80 g butter, plus extra for tin
160 g shortbread, made into fine crumbs
1 tbsp sugar
For the filling
900 g full fat cream cheese
250 g golden caster sugar
3 tbsp plain flour
1½ tsp vanilla extract
2 tbsp of grated lemon zest
1½ tsp lemon juice
3 eggs, plus 1 yolk
285 ml soured cream
Preheat the oven to 180°C (th. 6).
Line the base of a Ø 23 springform cake tin by putting a square piece of parchment paper or foil on top of the tin base and then clipping the side on so the paper or foil is trapped and any excess sticks out of the bottom. Melt 85 gram butter for the base in a medium pan. Stir in the shortbread crumbs and sugar so the mixture is evenly moistened. Press the mixture into the bottom of the pan and bake for 10 minutes. Cool on a wire rack.
For the filling, increase the oven temperature to 220°C. Mix the cream cheese at medium-low speed until creamy, about 2 minutes. Gradually add the caster sugar, the plain flour and a pinch of salt, scraping down the sides of the bowl and mix again.
Add the vanilla extract, the lemon zest and lemon juice. Whisk in 3 large eggs and 1 yolk and mix well.
Stir the soured cream until smooth, then measure 200 milliliters and add this to the egg mixture. Mix but don't over-beat, it should be smooth.
Brush the sides of the springform tin with melted butter. Pour in the filling and bake for 10 minutes.
Reduce the oven temperature to 110 °C and bake for 45 minutes. If you gently shake the tin, the filling should slightly wobble.
Turn off the oven and open the oven. Let cool in the oven for 2 hours. The cheesecake may get a slight crack on top as it cools. To take out the cheesecake of the mold, run a round-bladed knife around the sides to loosen any stuck edges. Unlock the side, and slide the cheesecake off the bottom of the tin and take off the parchment paper.