Mix first 4 ingredients together. Add milk to beaten egg yolk to make 2/3 c. Mix with flour mixture. Divide dough in half. Roll out half of dough in rectangle on wax paper. Put in pan. Sprinkle corn flakes on crust. Mix apples (cut and peeled), sugar and cinnamon. Spread on crust. Repeat other half of dough for top crust. Beat egg white and brush on top. Bake at 375 degrees for 40 minutes. Top with powdered sugar frosting. HINT: Roll out dough on wax paper the same size as 15x10x2 pan (top crust should be a little bigger), then flip over onto pan.