Step 2) Combine flour, corn starch, baking powder, baking soda, salt and cinnamon in a small bowl. Set aside.
Step 3) Whisk sugar, buttermilk, egg, egg white, corn syrup, oil and vanilla in a large bowl. Gradually stir in flour mixture until smooth. Fold in apples. Pour into a greased 8-inch square baking pan.
Step 4) Bake 35 to 40 minutes or until toothpick inserted in center comes out clean. Cool in pan on wire rack.
Step 5) For GLAZE: Combine powdered sugar and milk; stir until smooth. Drizzle over cooled cake, if desired.