Make Dough

1. Preheat oven to 375º
2. In a large bowl, stir together flour and salt. Cut in the shortening with a fork or dough cutter until it is in pea-sized pieces
3. In a measuring cup, beat egg yolk and add enough milk to measure ⅔ cup. Stir to mix and slowly add into flour mixture, starting with ⅓ of the liquid, mixing in with a fork or hands, and increasing until the dough comes together, not dry but not too sticky

Assemble Layers

1. Spray a 15½" x 10½" baking pan with nonstick cooking spray
2. Flour your work surface and rolling pin.  Divide dough in half and set one-half aside.  Gently roll half of the dough, rolling from the middle-out, to about a 17" x 12" rectangle
3. Roll the sheet of dough lightly around a rolling pin to transport to the baking pan. Unroll dough onto the baking pan, assuring that the bottom of the dish is completely covered with dough
4. Crush up the cornflakes a little with your hands and sprinkle them evenly over the dough
5. Top cornflakes with ⅓ of the apple slices
6. Mix together cinnamon and sugar in a small bowl. Sprinkle with ⅓ of the cinnamon-sugar mixture. Repeat with remaining apples and cinnamon sugar, in two additional layers
7. Roll remaining dough to a 15½" x 10½" rectangle and place over apples. Seal edges and cut 3-4 slits in the top for steam vents
8. Beat an egg white with a fork until frothy and brush on top

Bake & Add Glaze

1. Bake in 375º preheated oven for approximately 50 minutes
2. Mix together powdered sugar and milk to a syrupy consistency. When pastry is removed from the oven and still warm, drizzle with the glaze.
3. Allow pastry to cool before slicing into bars and serving