Preheat the oven to 350°. Remove your pie crust from the fridge and let it sit at room temp for 10-15 minutes so it will unroll without ripping.
Make the crumble topping by combining all the ingredients and stirring with a fork until it is completely combined. Set aside
Spray your cast iron skillet with some baking spray.
Fit the unbaked pie crust into the skillet.
Pour the apple pie filling into the pie shell and spread it out to fill the crust.
Sprinkle all the crumble topping over the apples.
Bake at 350° for 35 minutes.Let the pie cool for 15 minutes before serving.
Serve with ice cream! (or a drizzle of caramel sauce - you can half the caramel sauce recipe)
Notes
STORINGStore leftovers at room temp, covered, for up to 4 days.If you are going to keep the pie for more than 2 days I recommend storing it in a separate pan other than your cast iron. After 2 days the pie can start to take on a "metal" taste.