In a large bowl, combine flour and salt; cut in butter until mixture resembles coarse crumbs. In a measuring cup, combine egg yolk (set aside egg whites) and enough milk to measure 1/3 cup. Gradually add to the flour mixture, tossing with a fork until dough forms a ball.

Preheat oven to 350°F. Divide dough in half. Roll one portion into a thin 15x10-in. rectangle. Transfer to the bottom of an ungreased 15x10x1-in. baking pan. Sprinkle with cornflakes.

In a large bowl, combine apples, 1 cup sugar, 1-1/2 teaspoons cinnamon and nutmeg; toss to coat. Spoon over crust. Variation: sprinkle cranberries on top of apples

Roll remaining dough into a thin 15x10-in. rectangle; place over apple filling. Beat egg white; brush over pastry. Combine remaining sugar and cinnamon; sprinkle over the top. Bake 45-50 minutes or until golden brown.

For glaze, combine confectioners' sugar, vanilla and enough milk to achieve a drizzling consistency. Drizzle over warm pastry. Cool completely on a wire rack. Cut into squares