Preheat oven to 425 degrees F. Roll out piecrust and arrange in a 9-inch pie pan. Pour cranberries into crust to form a thick layer. In a medium bowl, sift together 2/3 cup sugar and flour. In a separate bowl, beat egg white until stiff peaks form, then fold into flour mixture. Slowly stir in cream until combined. Cover cranberries with remaining 1/3 cup sugar, then pour cream mixture on top. Bake pie for about 10 minutes, then lower oven temperature to 350 degrees F and bake for about 40 minutes more. Let pie cool before serving.