Preheat your oven to 350 degrees. Spray a 9" square pan with cooking spray. (If you don't have a 9" pan you can use an 8" pan, but may need to cook slightly longer as they will be a little thicker).
Cream the butter, sugar, egg and vanilla together till fluffy. Can do this in a stand mixer or bowl with beaters.
In another bowl, combine the flour, oats, baking powder & nutmeg. Add to the creamed mixture. Stir with a spatula or spoon combined.
Add the diced apples and cinnamon chips, mixing just till combined. Spread into the prepared pan.
Bake for 25-30 minutes or until a toothpick comes out clean.
Let cool before cutting into bars. Serve warm with ice cream or at room temperature. Store covered in the refrigerator.
Notes
If you can't find cinnamon chips (they are like chocolate chips but cinnamon :)) Then you can sub white chocolate and add ¼ teaspoon cinnamon to the recipe. -If you want to make this into a 9x13" just double the recipe.
Recipe by Baked in AZ at http://bakedinaz.com/apple-cinnamon-oat-blondies/