Preheat oven to 350 degrees.
Spray an 8 inch square pan with cooking spray. Set aside.
In the bowl of a food processor, combine flour, oats, brown sugar, cinnamon, and salt. Pulse to combine.
Add butter slices, a few at a time, pulsing after each addition.
Pulse until combined and crumbly.
Place 2/3 of mixture into prepared pan, and press evenly in bottom.
Bake for 15 minutes, or until just starting to brown.
Remove from oven and top with apple pie filling and remaining crumble mixture.
Return to oven and bake 40 minutes, until lightly browned.