Typical New York Cheesecake with crushed biscuits.
Melt the butter and add the crushed biscuits and stir in the granulated sugar. Press the mixture tightly into the base of a 23cm cake tin. Place into the oven and bake for 10 minutes (180°C/350°F/GasMark 4). Remove from the oven and leave to cool. Increase the oven to (200°C/400°C/Gas Mark 6). With a electric food mixer beat the cream cheese until creamy,then add the caster sugar and flour and beat until smooth. Increase the speed and add the vanilla extract,the lemon zest, then the eggs and the egg yolks and finaly add the double cream until the mixture is light and whippy. Butter the sides of the tin and pour in the filling. Transfer to the oven and bake for 15 minutes,then reduce the temperature to 100°C/200°F/GasMark 1/4 and bake for a further 30 minutes. Turn off the oven and leave the cake in it for 3 hours to cool and set. Enjoy the cake. :-)