Sift flour and salt into a large bowl. Using a pastry blender or 2 knives,cut in butter until evenly distributed and mixture resembles breadcrumbs. With a fork, lightly mix in sugar, egg and enough ice water to make a dough. Press into a ball and wrap in foil or plastic wrap. Refrigerate for 30 minutes. Preheat oven to 180ºC . On a floured surface, roll out dough to fit a 10-in flan tin with a removable bottom. Place dough in tin without stretching. FILLING  Beat cream cheese, oil, sugar, egg yolks, cornstarch, vanilla and milk in alarge bowl until smooth. Beat egg whites until stiff; fold into cream cheese mixture. Pour into pastry shell. Bake 50 to 60 minutes or until a wooden pick inserted in center comes out clean. Turn off oven. Let cheesecake cool in oven with door open slightly. Remove cooled cheesecake from tin and serve.