Preheat oven to 350 degrees F and then lightly coat a 9-inch baking pan with nonstick cooking spray and set aside.
Combine the flour, whole wheat flour, baking soda, cinnamon, and salt in a medium bowl. Then, in a separate, large mixing bowl, toss together the chopped apple and egg product. Stir in the white sugar, nuts, and applesauce. Finish by adding the flour mixtures and stir just until combined.
Pour the batter into the prepared pan.
To make the topping, in a small bowl mix together the brown sugar, flour, whole wheat flour, and cinnamon. Then, cut in the butter until crumbly and stir in the nuts. Sprinkle the topping over the batter in the pan.
Bake for 30 to 35 minutes or until a toothpick comes out clean. Cool in the pan for 10 minutes after baking, serve warm.