New York Cheesecake

Name: New York Cheesecake
Ingredients: 85g butter melted, plus extra for tin; 140g digestive biscuit, 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 egg, plus 1 yolk; 284ml carton soured cream; 142ml carton soured cream; 1 tbsp golden caster sugar; 2 tsp lemon juice