Add diced apples and all other ingredients (EXCEPT water/cider) at the top of the recipe card together in a bowl. Fold together so fruit is nice and coated.
Pour this into your cast iron pot or skillet.
In a bowl soften your butter and add all other crumble ingredients. Mix so everything is combined well.
Put this on top of your apples spreading it out as much as possible so it covers as much of the top as you can. Pour your cider or water over the top of everything.
Cover with foil and put into a preheated oven at 400 degrees F. for 45 minutes or until apples are softened to your liking.
Remove foil and turn oven to 425 degrees. Continue cooking for approx 5-8 minutes or until the top is a nice golden brown. Take out, allow to sit for 5 minutes to thicken and serve.