Preheat oven to 400. Prepare a 9"x 9 " baking pan with non-stick cooking spray.
In a large mixing bowl, add sliced apples.
Sprinkle vanilla extract over sliced apples.
In a small dish, mix spices and corn starch. Add mixture to sliced apples mixing well to coat.
Pour pure maple syrup over the apples and mix well. Pour into pan.
Push down a little if there won't be room for the topping; don't worry...it will cook down.
*Note: Optional tip. I like to pre-cook my filling for about 3-5 minutes in the large mixing bowl before placing it into the baking pan. This always ensures the apples are fully cooked.
Topping
Add nut butter, pure maple syrup, applesauce, and vanilla in a small mixing bowl. Mix well.
Add oats, cinnamon, and salt. Mix well.
Spread this mixture over the apples.
Bake for 25 minutes at 400 degrees. Set oven temperature to 350 and continue to bake for another 30 minutes. Cover with foil for the last 10 minutes to prevent over-browning.