85g butter melted, plus extra for tin 140g digestive biscuits, made into fine crumbs 1 tbsp sugar, granulated or golden caster 3 x 300g/11oz pack Philadelphia cheese, or other full-fat soft cheese 250g golden caster sugar 3 tbsp plain flour 1½ tsp vanilla extract finely grated zest of 1 lemon (about 2 tsp) 1½ tsp lemon juice 3 large eggs, plus 1 yolk 284ml carton soured cream 142ml carton soured cream 1 tbsp golden caster sugar 2 tsp lemon juice Want to see what this recipe costs at different supermarkets?