Preheat oven to 350 degrees Fahrenheit.

Combine the dry ingredients for the crumb topping in a bowl. Add in the oil and mix with your fingers to form a crumble texture. Set aside.

Grease an eight-inch square or 9×13-inch pan with baking spray or line with parchment paper.

Make the cake mix according to package directions and pour into the prepared pan.

Combine the filling ingredients in a large bowl and sprinkle the apple mixture over the cake layer.

Top with crumble and bake for 35 to 40 minutes or until the crumbs are golden.