Preheat oven to 180C. Line a 20cm cake pan (springform if you have one).
Melt 45g butter, stir in 80g finely crushed digestive biscuits and 1tbsp sugar. Press into the lined tin and bake 10mins (then let cool on wire rack).
Once base is out of the oven, increase oven temp to 210C. In a stand mixer or with an electric whisk on high, whip 450g full-fat cream cheese until creamy. Add 125g caster sugar, 1 1/2tbsp plain flour and pinch of salt. Scrape downsides.
Add 2 eggs (1 at a time), 1tsp vanilla extract, 1tsp lemon juice, 1tsp lemon zest and combine. Then on low, whisk in 100ml sour cream. Pour into the tin and bake for 10mins.
Drop heat of the oven to 100C and bake for 45mins. The cheesecake should be slightly wobbly. Turn off the oven, leaving cheesecake in for 2 hours. (Door open for creamy, closed for firmer/drier).
Combine 110ml sour cream, 1tbsp sugar and 1tsp lemon juice and pour on top. Cover the pan with foil and let cheesecake hang out in the fridge until ready to serve (at least 8hours). Run a knife around edges and serve!
Notes
You could easily add your own extras such as chocolate, biscoff biscuits, caramel sauce, etc – I’d suggest holding back on the lemon though!