- Preheat oven to 350°.
- Spray an 8x8 inch pan with cooking spray; Set aside.
- In a large bowl add the cake mix, quick oats, sugar, and cinnamon; Stir with whisk to combine.
- Pour melted butter over cake mixture and stir with whisk until mixture is crumbly.
- Spread and layer sliced apples over the bottom of pre-greased pan.
- Sprinkle crumbled cake mixture over the sliced apples.
- Bake for 35-40 minutes, until apples are tender and top is golden brown.