Preheat oven to 325 degrees F. Coat a 9-inch square baking pan with cooking spray.
In a large bowl, stir together all-purpose flour, whole wheat flour, sugar, baking soda, apple pie spice, and salt. Stir in egg, egg white, 3 Tablespoons melted butter, and canola oil. Stir in chopped apples. Press dough into prepared pan.
Bake 45 minutes or until a toothpick comes out clean. Cool in pan on a wire rack.
Meanwhile, in a 10-inch nonstick skillet, melt the 1 Tablespoon unsalted butter over medium heat. Add sliced apples; cook 8 to 10 minutes or until tender and golden, adding 1 Tablespoon of the water every 4 minutes and stirring until it evaporates. Remove from heat; stir in maple syrup.
Cut cake into 16 squares. Top with apple mixture and, if desired, whipped topping.
Tip: We do not recommend using a sugar substitute for this recipe.
1 fat, 1/2 fruit, 1/2 other carb, 1/2 starch