separate the eggs . Combine the egg Yolks , cream cheese , sifted flour , sour cream , lemon juice and rind and beat with am electric mixer until smooth and creamy . in a separate bowl , beat the egg whites until soft peaks form then gradually add the sugar to the egg white mix and beat till sugar dissolves then gently fold the milk through the egg white mix . now gradually beat the egg white mixture into the cheese mixture until smooth and creamy .