Preheat oven to 375 degrees F.
Grease 9x13" baking dish with cooking spray.
In a large bowl, beat together eggs, maple syrup, cinnamon, nutmeg, vanilla, salt, baking powder, oil, applesauce, and milk.
Stir in apple.
Fold in oats.
Pour into prepared pan.
Bake in preheated oven for 30 minutes, until just firm in the middle and golden brown on top.
Remove from oven and turn on broiler.
Sprinkle brown sugar over top of the baked oatmeal and broil for about 1 minute, until golden brown. Make sure to keep your eye on it!
Serve warm. Enjoy!