Preheat oven to 350 degrees. Grease a deep dish pie plat or large baking dish.
Combine sliced apples with sugar, cinnamon, and vanilla. Mix until all apples are evenly coated. Pour into prepared dish.
In a separate bowl, combine flour, oats, brown sugar, salt, and cinnamon Pour the melted butter on top, then mix until well coated and crumbly. Sprinkle this on the top of the prepared apples.
Bake in oven for 45-60 minutes until fruit is soft and top is golden brown. Allow to cool slightly and serve warm with vanilla ice cream if you desire.
Crock Pot Method: Add sliced apples to crockpot, and top with crumb topping. Cover and set on high for 4 hours. Let cool with lid off and serve warm with ice cream!
