Preheat oven to 375 degrees and line a sheet pan to place the baking dish on. This is just to ensure there is no overflow.
Toss apple ingredients together. Place into the bottom of a greased baking dish, This recipe is for one, but feel free to double or tripe the recipe for a larger batch.
Combine the oatmeal mixture and spoon over the top of the apples. Place the dish onto the lined baking sheet.
Bake for about 20-25 minutes or until golden and set. This will depend on your oven and how large your dish is. Check often as the oats could burn.
Cool slightly before serving and top with maple or pancake syrup, if desired.