Peel, core, and chop the apples.
In a large mixing bowl coat the apples with the flour and cinnamon.
Pour apple mixture into a 9" x 13" baking dish.
Topping
In a large mixing bowl add the softened butter, flour, sugar, and oats. Mix with your hands until it's like a dough consistency.
Take the mixture and crumble it on top of the apples.
Place in the oven for 70 - 80 minutes or until the apples start to bubble.